"Why our proteins have to die so we shall live" - A Lecture by Aaron Ciechanover
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| Lizenz | CC-Namensnennung - keine kommerzielle Nutzung - keine Bearbeitung 3.0 Deutschland: Sie dürfen das Werk bzw. den Inhalt in unveränderter Form zu jedem legalen und nicht-kommerziellen Zweck nutzen, vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen. | |
| Identifikatoren | 10.3203/IWF/C-13079 (DOI) | |
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| Produktionsjahr | 2006 |
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| IWF-Filmdaten | Video ; F, 68 min |
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00:00
MedikalisierungSystembiologieAusgangsgestein
01:13
Bukett <Wein>Hybridisierung <Chemie>Molekülbibliothek
02:07
Physikalische ChemieArzneimittelBiochemikerinAusgangsgesteinGrading
03:37
ReaktionsmechanismusTiermodellEnzymAktivität <Konzentration>Bukett <Wein>BiochemikerinStereoinduktionOmega-6-FettsäurenWursthüllePhosphatasenArzneimittelKlinische ChemieBase
05:06
BiochemikerinBukett <Wein>MenschenversuchTopizitätHaschischBisacodylSystemische Therapie <Pharmakologie>ProteolyseFunktionelle GruppeUbiquitin
06:53
Translation <Genetik>LactitolTopizitätGesundheitsstörung
08:14
ArzneimittelUbiquitinKrebsforschungProteineNobeliumProteolyseAbschreckenNobelpreis für ChemieSystemische Therapie <Pharmakologie>GesundheitsstörungLactitol
09:20
Internationaler FreinameCarbonatplattformSingulettzustandLactitolPathogeneseGesundheitsstörungRauschgiftGermaneSchwarzwälder Schinken
10:38
GenProteomanalyseGenomPrielMembranproteineRNSRibosomDNS-SyntheseProteineEukaryontische ZelleElektronische ZigaretteMeeresspiegelGenexpressionRegulatorgenSetzen <Verfahrenstechnik>Funktionelle GruppeProteolyseChemische ReaktionBaseReaktionsmechanismusChymotrypsinTrypsin
11:53
EnzymTrypsinChemische EigenschaftMembranproteineProteinogene AminosäurenProteinsyntheseMolekülWasserChemische FormelErdrutschNatriumSingulettzustandWerkzeugstahlPentapeptideNucleinsäurenArzneimittelChymotrypsinBukett <Wein>Eindringverfahren
13:00
QuerprofilVerdauungsenzymSystemische Therapie <Pharmakologie>ProteineZirkulationReglersubstanzTrypsinMembranproteineAntigenitätBleierzArzneimittelElektronische ZigaretteWasserstoffOperonGesundheitsstörungChemische EigenschaftTrennverfahrenTandem-ReaktionProteolyseX-Pro-Dipeptidase
13:52
FremdstoffQuerprofilPlasmamembranWollfaserAktivität <Konzentration>VerletzungFaserverbundwerkstoffGesundheitsstörungSystemische Therapie <Pharmakologie>InfarktMeeresspiegelZirkulationReglersubstanzProteolyseErbkrankheitElektronische ZigaretteKoordinationszahlChemischer ProzessAbschreckenCholesterinSingle electron transferSchlag <Landwirtschaft>Sonnenschutzmittel
14:54
ZirkulationReglersubstanzProteineDenaturierenZellzyklusSystemische Therapie <Pharmakologie>TranskriptionsfaktorAcetonEukaryontische ZelleUntereinheitKettenlänge <Makromolekül>ProteinfaltungProteolyseReaktionsmechanismusMolvolumenOperonMultiproteinkomplexEnzymBukett <Wein>Chemische Eigenschaft
16:23
ProteineRegulatorgenEnzyminhibitorCyclin-abhängige KinasenSchwesterchromatidenChemischer ProzessFunktionelle GruppeAbleitung <Bioelektrizität>Aktives ZentrumOrganische ChemieGlutaminsäureBiologisches MaterialKrebsforschungChronische KrankheitMembranproteineBukett <Wein>FieberBase
17:37
MetBukett <Wein>Chemischer ProzessKrankengeschichteKörpergewichtBukett <Wein>WerkzeugstahlProteolyseMeer
18:46
ProteineChemische EigenschaftChemischer Prozessf-ElementStoffwechselTyrosinAdvanced glycosylation end productsCholesterinBiosyntheseBiochemikerinProteinogene Aminosäuren
20:32
Bukett <Wein>SulfurBiosyntheseRadioaktiver StoffFettsäuremethylesterEdelgasInduktorNobeliumLactoseProteineFremdstoffGalactosidase <alpha->
21:29
TannineMannoseBiskalcitratumProtonenpumpenhemmerHarnstoffTrihalomethaneMühleMembranproteineProteineCobaltoxideStickstoffatomSenseProteinogene AminosäurenBenzolringCytologieEukaryontische ZelleMolekülProteolyseZutat
23:08
Eukaryontische ZelleAlauneAluminiumOrganellNobeliumChemische EigenschaftEukaryontische ZelleReaktionsmechanismusKathepsin GProteineEnzymMembranproteineLactitolSchussverletzungExtrazellulärraum
24:03
Chemischer ProzessOptische AnalyseProteineAlpha-1-RezeptorFettsäuremethylesterAutophagie <Physiologie>ExtrazellulärraumMolekülClathrinSekretionsvesikelLysosomLigand <Biochemie>MakromolekülChemische EigenschaftMembranproteineZusatzstoffZunderbeständigkeitAktives ZentrumWasserfallElektron <Legierung>ProteolyseWassertropfenCytosol
25:38
TillitX-Pro-DipeptidaseZusatzstoffEnhancerMembranproteineAbschreckenProteineSystemische Therapie <Pharmakologie>ZellzyklusUranpecherzAutophagie <Physiologie>Eukaryontische ZelleCycline
26:30
ChloroquinMembranproteineTamoxifenHydroxybuttersäure <gamma->OrlistatRauschgiftKrankengeschichteChloroquinArzneimittelBaseInhibitorGesundheitsstörungLysosomKarsthöhleChemische EigenschaftThylakoidSubstrat <Boden>Eukaryontische ZelleAktivität <Konzentration>
27:42
MembranproteineTamoxifenMagmaBukett <Wein>ClusterProteineChloroquinMembranproteineExtrazellulärraumProteolyseSetzen <Verfahrenstechnik>Systemische Therapie <Pharmakologie>Eukaryontische ZelleTiermodell
28:45
MembranproteineQuellgebietTritiumMakrophageLysosomSubstrat <Boden>KryptandenWassertropfenLysosomExtrazellulärraumMembranproteineProteineEnzyminhibitorX-Pro-DipeptidaseStoffwechselExplosionGesundheitsstörungKomplikationEukaryontische ZelleSystemische Therapie <Pharmakologie>MenschenversuchGradingMeeresspiegel
30:26
KernreaktionsanalyseX-Pro-DipeptidaseFruchtmarkAktivität <Konzentration>ElutionAusflockungPoröser StoffGranulozytopoeseLot <Werkstoff>ErythrozytEukaryontische ZelleAktives ZentrumZirkulationInduktorSaccharomyces cerevisiaeEnzymChemische EigenschaftLysosomX-Pro-Dipeptidase
31:35
LactoseBiskalcitratumMembranproteineKrankengeschichteSubstrat <Chemie>BiochemikerinAktivität <Konzentration>GlobineCytolyseX-Pro-DipeptidaseLactitolNiederschlag <Chemie>KunstlederArzneimittelEukaryontische ZelleQuellgebietDeprotonierungOktanzahl
32:48
EnzymMembranproteineAktivität <Konzentration>BiophysikCelluloseCoiled coilEnzymUbiquitinSystemische Therapie <Pharmakologie>GenomGradingGenMembranproteineAntikörperProteineT-LymphozytAlpha-1-RezeptorGewürz
33:41
Weibliche ToteBiochemikerinTetrapeptideFunkeMembranproteineSäureAmine <primär->ProteineMembranproteineSubstrat <Chemie>Systemische Therapie <Pharmakologie>Chemische EigenschaftAktives ZentrumReaktionsmechanismusChemischer ProzessX-Pro-DipeptidaseCytosol
34:37
BiochemikerinLysinSäureMembranproteineAmine <primär->TetrapeptideDerivateSystemische Therapie <Pharmakologie>ZirkulationX-Pro-DipeptidasePlasmamembranLysosomSubstrat <Chemie>WildbachKochsalzSammler <Technik>Memory-EffektChemische EigenschaftKrankengeschichteElektron <Legierung>Posttranslationale ÄnderungKörpergewichtThermoformenMembranproteine
35:40
AmidasenLysinTetrapeptideBiochemikerinFunktionelle GruppeFunkeSäureDerivateMembranproteineAmine <primär->Chemische StrukturUbiquitinierungSystemische Therapie <Pharmakologie>Chemische StrukturKonjugateMembranproteineTargeted drug deliveryX-Pro-DipeptidaseReaktionsmechanismusAllmendeGesundheitsstörungAtomorbitalAmine <primär->RückstandChemische ForschungLysinProteinePosttranslationale ÄnderungWindsichter
36:40
Chemische StrukturUbiquitinierungSiebCytolyseChemische BindungSubstrat <Chemie>MembranproteineMembranproteineUbiquitinChemische EigenschaftKettenlänge <Makromolekül>X-Pro-Dipeptidase
37:36
UbiquitinierungMembranproteineSubstrat <Chemie>CytolyseChemische BindungMayonnaiseChemische EigenschaftReaktionsmechanismusSystemische Therapie <Pharmakologie>AbschreckenEssenz <Lebensmittel>MeeresspiegelSetzen <Verfahrenstechnik>X-Pro-DipeptidaseMembranproteineProteineSense
38:42
WollfaserUbiquitinSystemische Therapie <Pharmakologie>Substrat <Chemie>ArzneimittelWursthülleUbiquitinierungEnzymPhosphorylierungBaseProteineChemische ReaktionMembranproteineElektronentransferGenomKettenlänge <Makromolekül>AbschreckenFreies ElektronFunktionelle GruppeOzonFleischerBindungsenergie
40:31
EnzymMembranproteineUbiquitinierungChemische StrukturElektronenstrahlschmelzenUbiquitin-Protein-LigaseHydrophobe WechselwirkungSystemische Therapie <Pharmakologie>Kettenlänge <Makromolekül>Ligand <Biochemie>Initiator <Chemie>ArzneimittelSubstrat <Chemie>DiamantSubstrat <Boden>Rauschgift
41:22
UbiquitinierungGesundheitsstörungSystemische Therapie <Pharmakologie>OberflächenchemieMembranproteinePosttranslationale ÄnderungEukaryontische ZelleUbiquitinPlasmamembranProteineKernporeLysosomUbiquitinierungSingle electron transferMicroarray
42:52
UbiquitinierungCalciumhydroxidOrlistatTrennverfahrenRückstandLysinUbiquitinierungKettenlänge <Makromolekül>ProteineTiermodellSystemische Therapie <Pharmakologie>PhosphorThermoformenFließgrenzeTranslation <Genetik>Posttranslationale ÄnderungOktanzahlHerzfrequenzvariabilitätTorsionssteifigkeitKernporeUbiquitinEukaryontische ZelleKrebsforschungTillitAktivität <Konzentration>MembranproteineRNS-SyntheseChemische EigenschaftGesundheitsstörungFunktionelle Gruppe
44:50
MedroxyprogesteronMembranproteineGallenfarbstoffeUbiquitinierungMolekulardynamikStoffwechselwegX-Pro-DipeptidaseEnzymSterblichkeitSimulation <Medizin>SchieferFunktionelle GruppeFaserplatteTrennverfahrenProteolyseMembranproteineUbiquitinProteinePharmakokinetikLactitolBukett <Wein>
45:46
MembranproteineX-Pro-DipeptidaseStoffwechselwegUbiquitinierungMolekulardynamikEnzymMedroxyprogesteronBukett <Wein>Proteinglutamin-Glutamyltransferase <Proteinglutamin-gamma-glutamyltransferase>Substrat <Boden>Gangart <Erzlagerstätte>SubstitutionsreaktionWursthülleMembranproteineKrebsforschungUbiquitinSystemische Therapie <Pharmakologie>TiermodellChemotherapieRauschgiftBleiglanzProteineGesundheitsstörungFunktionelle GruppeOperonReglersubstanz
46:41
ZelldifferenzierungGesundheitsstörungReglersubstanzProteineUbiquitinBukett <Wein>Setzen <Verfahrenstechnik>ProtoonkogenChemischer ProzessAbleitung <Bioelektrizität>MembranproteineRNS-SyntheseSystemische Therapie <Pharmakologie>Operon
47:38
BaustahlMembranproteineKrebsforschungKrebsforschungTumorGenomPhenobarbitalStrahlenschadenEukaryontische ZelleProtein p53BaseSenseQuellgebietZellzyklusMolekülStoffwechselKrankengeschichteSingle electron transferTerminations-Codon
48:35
MembranproteineKrebsforschungFirnProtein p53KaschierenProtoonkogenUbiquitinSystemische Therapie <Pharmakologie>KrebsforschungFrühcarcinomMembranproteine
49:28
BleierzStrahlenschadenProtein p53MembranproteineSyndromFlammschutzGesundheitsstörungAppetitBleierzChemisches Element
50:29
MembranproteineVolumenhafter FehlerElektronische ZigaretteOxidschichtProtoonkogenAcetonSyndromGenomMultiproteinkomplexProteineProtein p53StratotypPhenobarbitalTeststreifenChemische EigenschaftHessischer BauernverbandTransformation <Genetik>SingulettzustandDNS-SyntheseFrühcarcinomBukett <Wein>KrebsforschungAntikörperAlpha-1-Rezeptor
51:54
RauschgiftProtoonkogenf-ElementDurchflussTumorX-Pro-DipeptidaseProteaseinhibitorElektronische ZigaretteChemische EigenschaftAktives ZentrumChemische StrukturProteineMolekül
52:58
GefriertrocknungKrummdarmSubstrat <Chemie>BortezomibRauschgiftBleierzKrebsforschungBoronsäurenRückstandThreoninAktivität <Konzentration>ReaktionsmechanismusAktives ZentrumMeeresspiegelMembranproteineSetzen <Verfahrenstechnik>ArzneimittelSingulettzustandPlasmozytomAntikörperBukett <Wein>Eukaryontische ZelleWursthülleAntigenChemieanlageHomöopathieTiermodellImmunglobulineEffektorzelleDiamantähnlicher KohlenstoffNobelium
54:28
ArzneimittelKaugummiImmunglobulin ABiomarkerBiologisches MaterialSystemische Therapie <Pharmakologie>Interkristalline KorrosionMassenspektrometerBukett <Wein>OnkologieTumorKrebsforschungAntikörperMembranproteineGesundheitsstörungGiftWeibliche Tote
55:48
MegakaryozytBruchverhaltenGranulozytopoeseFleischerTumorEffektorzelleIonenbindungParasitismusGesundheitsstörungHämatitMembranproteineEukaryontische ZelleKrebsforschungHomogenes SystemPathologin
56:46
LeukozytGranulozytopoeseRemissionStoffpatentTumorStrahlenbelastungThermoformenKrebsforschungDNS-SyntheseChemotherapieRauschgiftDoxorubicinTeststreifenMähdrescherOnkologieGesundheitsstörungSturzwasserbewässerungIndololeSeafloor spreadingWursthülle
57:58
DNS-SyntheseProtoonkogenZellwachstumBiologisches AlterSchubspannungOxideInterkristalline KorrosionKernspindelEnzyminhibitorHope <Diamant>MähdrescherArzneimittelforschungTelomerisationMolekülProtein p53Aktivität <Konzentration>Systemische Therapie <Pharmakologie>SchubspannungDNS-SyntheseProtoonkogenEukaryontische ZelleDNS-SchädigungGesteinsbildungWeibliche ToteStrahlenschadenZellzyklusZellwachstumSenseZellteilungKlinischer Tod
59:01
EnzyminhibitorProtoonkogenKrebsforschungProtein p53SchubspannungGenRNS-SyntheseUbiquitinTranskriptionsfaktorReaktionsmechanismus
59:55
CycloalkaneKlinischer TodEukaryontische ZelleDNS-SyntheseEnzyminhibitorLagergangEinschlussProtoonkogenDesacetylierungSchubspannungPhosphorylierungProtein p53ZirkulationKlinischer TodEukaryontische ZelleDNS-SchädigungInduktorZellzyklusStereoinduktion
01:00:51
GenEnzyminhibitorKrebsforschungTetrahydrothiophenAdvanced glycosylation end productsProtein p53UbiquitinPhosphorylierungChemischer ProzessDesacetylierungMeerProtoonkogen
01:01:42
GenKrebsforschungEnzyminhibitorInhibinf-ElementProtoonkogenTumorAktivität <Konzentration>Systemische Therapie <Pharmakologie>MolekülInhibitorEnzymAbschreckenMembranproteineRauschgiftWassertropfen
01:02:34
f-ElementCycloalkaneEukaryontische ZelleHydrochlorothiazidChemische StrukturRauschgiftMembranproteineSubstrat <Boden>Protein p53InhibitorBindungsenergieAbschreckenMolekülElektronische ZigaretteZellzyklusZellfusionElementenhäufigkeitStratotyp
01:03:28
Eukaryontische ZelleCalciumhydroxidDoxorubicinPhasengleichgewichtReglersubstanzZellwachstumZellzyklusTumorEukaryontische ZelleDNS-SyntheseRauschgiftBukett <Wein>QuerprofilSystemische Therapie <Pharmakologie>Stoffwechselweg
01:04:58
High throughput screeningProteineStoffwechselwegSystemische Therapie <Pharmakologie>
01:05:50
LeucinAlauneIonenbindungUbiquitinSetzen <Verfahrenstechnik>VollernterMembranproteineSystemische Therapie <Pharmakologie>PeriodateBukett <Wein>UbiquitinierungKooperativitätHalbedelsteinChemische ForschungPharmazieAktives ZentrumKettenlänge <Makromolekül>
01:06:56
Aktivität <Konzentration>NobeliumMembranproteineSystemische Therapie <Pharmakologie>
01:07:53
GesundheitsstörungKrebsforschung
Transkript: Englisch(automatisch erzeugt)
00:22
Dear Vice President, dear Dean of the Medical Faculty, dear colleagues, and honorable guests, it's a great pleasure and honor for me on behalf of the Center for Molecular Physiology of the Brain to welcome and introduce our guest speaker today, Professor Arun Chikhanova from Haifa.
00:41
Let me briefly introduce Arun Chikhanova to you to know a little bit about his CV. He was born in 1947 in Haifa. His parents came from Poland as followers of the Zionist movement in the early 20s, which was initiated by Benjamin Herzl around the century.
01:02
So they already came to Israel before the Second World War. He was born right after the war, and he was studying nature as a child already. His father was a clerk in a law firm and later became a lawyer. His mother was a housewife and English teacher.
01:22
And his father always motivated him to use the huge library they had. And Arun also told me that he was reading books with very much fascination. However, even more so, he was interested in nature itself, and he tried to explore nature. And there's a short episode that those books in the library
01:42
were not used by him always only for reading, but also for pressing leaves and flowers and even small reptiles. So I learned that somehow his family not only appreciated these things, because there were also holy books involved in that. So there was a very early priming
02:01
of his interest, which were further substantiated in high school later, where he met inspiring teachers and got interested in biology and biochemistry, physics, and mathematics. Nevertheless, he did not study biology, but decided to study medicine.
02:20
That was a compromise for him in several ways, because first of all, it allowed him to postpone his military service at that time and get further funds from the state to study and get a university education. Because his parents had died, meanwhile, and he was supported by his aunt and his older brother.
02:42
Another compromise for him was because he got a practical education in a profession which was always kind of thought to be one of the ultimate ones to be a medical doctor. So in a fierce competition, he got one of the few places at the only university which offered a medical education
03:03
at that time, the Hadassah in Jerusalem in 1965. And he started with enthusiasm to study medicine. And the preclinical years, I understand, were very good and successful. But when he first had to treat patients,
03:21
he got the impression that this is not the final way he would go, because he was often left just with no treatment that he could offer to them. So at that time, there was an interesting possibility offered in the medical faculty, which allowed
03:42
him to do a master's thesis in biochemistry for one year. And he took this chance and started in 1969 to examine the mechanisms of fatty liver induction in a rat model under the guidance of two excellent biochemists, Jacob Bartana and Benjamin
04:01
Shapiro. In his thesis already, he could demonstrate a pathogenetic role of an increased activity of phosphatidic acid phosphatase, a key enzyme involved in D- and triclosarid hemiostasis. So this experience with basic research during his master's thesis, I think,
04:21
was important for him to show him that there are alternative ways in clinical medicine. And that is translational research and medically oriented research within medicine. Nevertheless, he had to finish his medical teaching, and he graduated from med school in 1972.
04:42
At that time, a very young and talented biochemist, Dr. Avram Hershko, was recruited to the newly founded faculty of medicine at the Technion in Haifa. And since Aaron knew that this new biochemist was recruited,
05:00
he thought he should approach him and ask for an experimental medical thesis. So he asked him, and he got one thesis. But the topic was not very well-defined at that time, as he told me. So in between these years, he spent the lab time
05:20
and the education in the clinical departments. He learned to switch back and forth. And he also got a training, of course, in the clinical subjects. In the time in the army which followed afterwards, he served as a physician on a missile boat fleet, but also spent some time in the research and development unit of the army.
05:42
But he maintained tight connections with the Avram Hershko lab. He continuously taught biochemistry to medical students during that time. At that time, the Hershko group was mainly studying intracellular proteolysis.
06:01
And when Aaron asked him for a project, he offered him to study a completely new subject, which was a protein degradation system that has not been described so far. So he was kind of left with a vague idea that there might be a system which has not been described at that moment
06:22
besides the lysosomal system. So in the following years, he started first to do a training in surgery as a resident, but realized that his real love was biochemistry. And then he finally switched over to do his graduate studies with Avram Hershko. And in these days, they probably
06:42
had the first ideas about how the system that he will describe later, the ubiquitin proteasome system, would work. In 1981, he went to the MIT to work with Harvey Lodish,
07:00
basically carrying out his own project further. So he did not go as a postdoc into another lab and got another topic, but he had better conditions to work, but stayed with his topic during that time. In 1984, after three years at the MIT, of course, as an excellent young scientist, he got lots of offers to stay in the US,
07:21
and he was tempted to do so, but finally decided to go back to Israel in his home country. And Avram Hershko again helped him to get an independent research position at the Technion in Haifa, where he still is. So the Technion has traditionally been a school of engineering,
07:41
and the leaders of the Technion have not that much been exposed to medical and biomedical sciences. And I learned that during these years, they even thought about closing down the med school. And only in the recent years, they understood how important biomedical research and translational research, as we can learn from Aaron's
08:02
experiments, are for the development also of new therapies, and of course, offspring of biomedical research, and especially those institutions which follow those. So we are glad that Aaron was successful in maintaining the lab at the med school in Haifa,
08:22
that he is able to work together, also with us in several European networks, and that he can carry out this research furthermore. As you know, Aaron has received many honors and awards. He has several visiting appointments at the most distinguished institutions in the world,
08:40
like in Harvard, or at the Voshu in St. Louis. He received the Lasker Award in 2000, and in 2004, the Nobel Prize for Chemistry, together with Afram Hershko. Today, he will tell us about the important implications of the ubiquitin proteasome system, not only for our understanding of specific protein degradation in general, but for our understanding of cancer
09:04
and also neurodegenerative disorders, with the title, which is indicated here, why our proteins have to die, so we shall live. So thanks again for coming to getting in. Despite of your tight schedule, we're looking very much forward to hear your talk. Thank you, Aaron.
09:33
Thank you, Mathias, for inviting me. It's been a pleasure to collaborate with you for the last two years, since we started the NeurONI program.
09:41
And what I'm going to tell you today is in a very short, maybe 45 minutes or so, how along short 30 years, one can go for a vague idea that basically doesn't exist and people don't believe, into a huge development of a huge platform in biology,
10:01
but even more important or as important, understanding of pathogenesis of multiple diseases, and then development of drugs. So we have gone a long, long way since we started our journey into this black forest, if to use a German term, of not knowing at all
10:23
where we are going into actual drugs in the market and patients lying in hospitals and being treated. So this has been a marvelous journey for me, and I witnessed it all from day one, I would say. So at the mid-70s, when we entered the field, there was no field, basically,
10:41
because most of the people were interested in how the genome is translated into the proteome. This was the post-Watson Creek aftershock, when people were interested of how DNA is replicated and how DNA is transcribed into RNA and how RNA is translated into proteins and ribosomes
11:01
and so on and so forth, and nobody asked the question, well, we are synthesizing our proteins, what happened to them? At the end, and if people thought about it, and there were very few people that thought about it, they thought about it as a marginal side question, as garbaging, as scavenger, and all the regulation.
11:22
If people thought, oh, proteins have to be regulated, they should be regulated at the gene expression level. Nobody thought about the other side. They can be a regulation of the other side, and this was a garbage type of a mechanism that didn't attract basically any attention. Very few groups were around.
11:40
So things have changed, and I want to tell you how they were changed. So the basic reaction of proteolysis is the same, and it has been there forever, since people discovered trypsin and chymotrypsin and gastrointestinal tract enzymes, and it's taking a nice protein that has a peptide bond and putting one molecule of water into it
12:01
and taking the two amino acids apart. If you think about protein synthesis, the opposite, it's exactly that. I mean, basically, if you want to think of modern biology, it's encompassed in this single slide because all the purpose of what we are doing with DNA and RNA is just putting two and three and four
12:20
and multiple amino acids together at the right order, and if there is a mistake in the order or something happens, then we are in a big trouble. But basically, we are playing with molecules of water. We are putting them, we are either extracting them and generating a peptide bond, synthesizing our machineries, or taking them apart. Now, if we think about, so then, what's so important
12:42
about it, if people knew about trypsin and chymotrypsin for generations, then why to go back into this question? And the going back into this question has to do with topology, with hierarchy, and where it occurs in the body. And I'll use a lot of medicine during my talk and where we learned from medicine because it's very important.
13:00
So the most primitive, or simple, I would say, not primitive, proteolytic system is in the gastrointestinal tract where every protein is being digested. We take proteins and we digest them. It's nondiscriminatory, nonspecific, and the purpose is dual, to remove antigenicity and to derive energy. Now, once we are crossing the lining of the gastrointestinal tract
13:21
and we are inside the circulation, we immediately in a different world. We are in a world of control. We cannot afford trypsin or digestive enzymes just going wild and acting wild in the circulation. And again, if we look into medicine, I'll bring you just to example where aberrations in the system lead to severe disease,
13:41
called proteolytic system. So if you think of the blood coagulation system, it's a bona fide cascade of proteolytic events that one protease becomes active and activates the next one that becomes active, and at the end, fibrinogenics convert to fibrin. So think about the major killer in the Western world, myocardial infarction.
14:00
It's an end process, obviously, following accumulation of cholesterol in atromatotic plaques, but at the end, coagulation occurs, coronaries are occluded, and part of the heart or the whole patient is dying. And the opposite, a whole set of genetic diseases. Hemophilias, where blood coagulation factor is missing
14:22
and the patients can bleed profusely from a minor injury. And I can bring you many more proteolytic systems that lead in the circulation that lead to diseases, alpha-1 antitrypsin, alpha-1 anti-chymotrypsin, that leads, the deficiency of them lead to excess of proteolytic activity
14:40
and to emphysema and to liver diseases. And I can bring you other multiple examples when the system goes wrong. Now, this is extracellular. Now, once we move into the cell, things become much more complicated because the level of control and specificity that is required in the cell is much higher than even in the circulation. So why do we need to degrade our own proteins?
15:03
And again, from now on, I shall limit myself only to intracellular proteolysis. Why at all we need to degrade our own proteins? And there are three main reasons. One major reason that we didn't appreciate maybe until less than a decade ago is quality control. Now that we start to understand mechanisms of diseases,
15:23
we understand what's quality control. Basically, all the neurodegenerative systems are aberrations in quality control because we are collecting proteins that should be otherwise degraded. So that's quality control problem. We are accumulating different proteins that shouldn't be there. So quality control has to do with denaturation of enzymes,
15:41
with misfolding of enzymes, with mutated proteins that cannot be removed, that contains all kinds of chains that shouldn't be there, and even with simple things like proteins that are part of multi-subunit complexes, not all the subunits are synthesized in the same equimolar amounts, and we need to remove excess of non-used subunits.
16:03
So that's also quality control, though the proteins are normal. Then we need to control processes. So these are normal proteins that have nothing to do, they are not wrong, they are not misfolded, but have to be removed at a certain time. So you can think of any transcription factor that you don't need anymore, NF kappa B, meek, force. You can think of the entire cell cycle.
16:20
The whole cell cycle is riding over removal of different regulators at different times. Cyclin, cyclin-dependent kinases, cyclin-dependent kinase inhibitors. Chromatid gluing proteins. All these proteins need to be removed at a certain time so the process can go on. And then obviously one can think of differentiation and morphogenesis.
16:41
In order to keep the differentiated state and the appropriate morphogenesis of organs, we need to remove certain proteins so they will not be there. They had been there before, they fulfilled their function until the tissue had made a decision, and now we don't need them anymore. So three good reasons why we need to degrade proteins. Now the extent of the process is huge.
17:04
Basically we are destroying daily, we are removing daily, five to seven percent of our proteins. It's a huge process quantity-wise. And I can give you an example, that's as you see, once it's accelerated, if you take a gunshot-wounded patient
17:21
or you take a patient in chronic infections or cancer-induced cachexia, the patient is losing kilograms of body mass, in no time basically. Take a patient and he has a little bit of a fever and some infection within two weeks, 10, 15, 20 kilograms of body mass are gone,
17:40
completely gone. But even normally we are removing every day two to three kilograms of our weight, but we are still able to exchange them. So the process is not an negligible one, it's a major process. Now let's go a little bit to the history, because what I want to emphasize to you is where we were in the field, and I think that this is a very good educational lesson,
18:01
because we basically, like any scientist I believe, though I'm not familiar with the history of other fields or so much so, we collected some stones. So once we entered the field, there were heavy pieces of knowledge there, and all what we had to do is to collect them, to draw, to understand that something is still missing,
18:20
and then to add the missing piece. But a lot of information was there. So no doubt the founding father of modern proteolysis was Rudolf Schoenheimer, he grew up here in Germany, but then escaped Germany in the mid 30s when the Nazis rose to power and went to the United States, like many others, including Konrad Bloch, and he ended up in the same department as Konrad Bloch,
18:42
in the Department of Biochemistry in Columbia University that because they absorbed so many, Jewish scientists became at that time probably the best department of biochemistry in the world. This was the beginning, I think, of the rise of American science, and Rudolf Schoenheimer was not interested in science, he was interested in methodology, and it's interesting because for us,
19:00
from time to time, scientists, we think, oh, the people that develop methods are, but we don't realize that the method, science will not move without methods, it's hand to hand process. And along with Harold Urey, he developed all kinds of isotopes, and Harold Urey was at the department at the time, and they used all kinds of isotopes to study and to trace down all kinds of metabolic processes.
19:21
So Konrad Bloch was there, and he elucidated, obviously, the cholesterol biosynthetic pathway, and others elucidated other pathways, and no doubt that Rudolf Schoenheimer was even the person behind Konrad Bloch. They had many papers together. It's a very interesting story. He died untimely at the early 40s, and among one of the experiments that he did,
19:42
he used N15. This was a heavy isotope labeled tyrosine, and he gave it to rats, and he found that the amino acid goes into the proteins and comes out. So, I mean, for us, we are taking it for granted. What's so fun, what's the fuss about the experiment? The fuss about the experiment that it was a contradiction to the paradigm in the field.
20:01
And once people are coming with something that is not in line with the paradigm, they are rejected. So people don't, it takes years to accept it. And the paradigm in the field was that proteins are static, that they don't exchange. We have our proteins, we are being born, we synthesize all our proteins to the age of 15, 16, whatever, and then we walk with them
20:21
through seven, eight decades until we die with the same very proteins. People really believed in the staticity, in the fact that proteins are static. And you will see the word of coming from very famous scientists. And Rudolf Schoenheimer broke this paradigm. But then, now we are moving 10 years,
20:41
this was the early 40s, we are already in the mid 50s, we'll jump very quickly along the decades. We are in the mid 50s and two very famous scientists, Jacques Monod, Nobel laureate himself from the Institut Pasteur. Actually, many of you know him and don't know him. We know him because every day we are using the trick that he developed, it's not a trick, it's a very sophisticated method,
21:01
in order to induce proteins in bacteria. By throwing IPTG into bacteria and activating the lac operon, that's what the Jacques Monod story, the Jaco Monod and Levov discovery, and David Hognes, no doubt the founding father of modern fly genetics, now at Stanford.
21:24
They studied the stability of beta-galactosidase and they found that beta-galactosidase is stable. And then they went on to conclude for any other protein and they said that to sum up, there seems at present to be no conclusive evidence that proteins,
21:40
molecules within cell of mammalian tissues are in a dynamic state, so they are static. And again, they say, moreover, our experiments have shown that proteins of E. coli are static. So in the mid 50s, people are coming and tell the scientific world, well guys, there is no problem. Don't study anything because there is no problem. You don't have to study degradation because proteins are not degraded.
22:00
So this was an extremely influential paper. I mean, I can understand those days that very few papers came out, the scientific community was not that big. Such a paper was extremely influential and basically shut down the field. But meanwhile, some leakage started around. And one leakage was a very obscure paper
22:21
that came in JBC but attracted our attention later on, showing that protein degradation is energy requiring, which was very strange thermodynamically. So here is just the release of labeled amino acid from tissue, doesn't matter. And once you exchange the atmosphere from oxygen to nitrogen, you go down. This didn't make any sense thermodynamically
22:42
because proteins are like fuel, are like benzene, like gas. I mean, they are high energy ingredients. We eat them in order to derive energy. So why to put more energy in order to degrade them? So this didn't make any sense and it was kind of forgotten. It was put in the literature and forgotten from the heart of anybody. And it took decades to rediscover it.
23:02
And then came Christian De Div, wonderful cell biologist in the mid-50s also, and he discovered the lysosome of the Nobel Prize himself in the mid-60s. And the lysosome is a nice organelle. It sits in the cell. And inside it, it's surrounded by membrane, obviously. And inside there is a whole cohort of proteases,
23:22
exactly like in the gastrointestinal tract, cathepsins and different enzymes. And the world breathed again. Here is the mechanism. So people started to be convinced that proteins are degraded and the only question was, what is the mechanism? And here is the mechanism. So this discovery, basically, with all its beauty and its importance,
23:41
shut the field again for another almost 25 years. People got the notion, accepted the notion, that the lysosome is the organelle that degrades intracellular proteins. And they believed so for almost 25 years, from the mid-50s all the way to the late-70s. And how they degrade the proteins?
24:01
Well, extracellular proteins was not a problem. Macromolecules like ligands of receptors, like the LDL, the famous work of Brown and Goldstein, and insulin, pedrocorticuses, and you can just scan modern biology, are being bound to a receptor and then they go in via clustering-coated vesicles
24:21
and the whole series of vesicles, they go to the lysosome. So the question of extracellular proteins that's coming from the outside was not a problem. The problem was, again, is the lysosome involved in degradation of intracellular proteins? And the answer that Christian de Divivis himself and other people gave was yes. How? By microautophagy. So here, you can see a small microautophagic vesicle
24:43
that pinches off the cytosol, makes a bleb. Here, this is a nice electron micrograph, makes a bleb, and then the contents of the bleb are being poured into the lysosome and being degraded. But don't forget that this bleb contains every single protein that is in the cytosol.
25:02
25,000 different proteins are sitting in this droplet. Now, if you do a simple experiment in the lab and you take any protein that you want and you mix it into lysosomal proteins, it will be degraded within a few minutes. So the process is not selective. And then people started to see that protein degradation
25:23
is very selective and different proteins have different stabilities. So some proteins leave only few minutes and some proteins leave many, many hours. Three logs difference in time scale, which could never be explained based on this microautophagic blebbing.
25:41
Because as I told you, this bleb contains all the proteins. So they should be degraded at the same time. So how is it that proteins have different stabilities? Not only that, but at that time, Tim Hunt and Leland and Paul Maris described the cell cycle, another major development in biology.
26:02
And during the cell cycle, proteins have the same protein changes its stability. So cyclin is very stable along most of the cell cycle, but then degraded during mitosis. That's mitotic cyclin and G1 cyclin is degraded during G1. So people started to realize that the system must be very selective.
26:22
And the lysosome did not provide this explanation for specificity. And there were other arguments that were coming. Some came from medicine by Brian Poole. And Brian Poole, again, I will not go into the details, brilliant scientist at the Rockefeller University, he studied malaria. So lots of knowledge came from medicine.
26:42
And he studied malaria and in Germany, you don't know it, but in my country, we do know malaria. And actually we got it in several times, even in modern history. And malaria is a parasitic disease that is being treated by chloroquine. This is one of the drugs that is being used. And chloroquine has been known for years
27:00
as a lysosomal inhibitor. It inhibits the lysosome simply because it's a base. And the base is going into the lysosome. And there it neutralizes the intralysosomal low pH. I forgot to tell you, the lysosome has a very low pH. Inside it's lumen of about four and a half to five, which is necessary in order to keep the protease active.
27:22
They are acting optimally at low pH. And once you neutralize it and you bring the pH up, the lysosome is basically dead. So it's a very nice trick that you can use in any culture cell. Add a little bit of chloroquine into the medium of the dish and the lysosome is shut down. So Brian did a very simple experiment.
27:41
And he tested lysosome on the degradation of either endogenous proteins or proteins that come from the outside. And he found that endogenous proteins, intracellular proteins, are not affected at all, or almost not at all by chloroquine. So you can inhibit it by 17% in one experiment, 4% in another, but nothing really important, significant.
28:02
While exogenous proteins, proteins that come from the outside, are degraded by the lysosome because their degradation can be strongly inhibited by chloroquine. So he concluded, he was the, in my opinion, Brian Poole was the most important researcher in the modern era because he predicted
28:22
two types of proteolytic machineries in the cell. One is the lysosome that will be involved in the degradation of extracellular proteins because those proteins can be inhibited. And one, another system that he couldn't even name and I'll just read you how he wrote it in a very poetic way. I mean, this is prophecy of scientists.
28:42
It's just really marvelous. And what he wrote is the following. Let's look at the details of the experiment. The exogenous protein, extracellular proteins, will be broken down in the lysosome. While the endogenous proteins, those that cannot be inhibited by lysosomal inhibitors, will be broken down wherever it is
29:01
that endogenous proteins are broken down during protein turnover, wherever it is. No name. And this is late 70s, this is 77. He wrote it in 77 and left it in the literature. He died also untimely from complications of diabetes and other diseases.
29:20
But he knew that the cell is equipped with another system that he called wherever. And we entered the field exactly at the time. I became a graduate student with Avram. Avram was, at that time came from post-doc. He was very young scientist and I was his second graduate student. Actually, we were two graduate students starting in a mini group.
29:42
And the lab was very poor. He just started the lab in a new, and I was attracted to him because he told me, yes, I have a subject for you. But the subject has only a title. The title will be, we are going to find together a system that is non-lysosomal and degrades in an energy-dependent manner
30:01
intracellular proteins. And I said, okay, Avram, but what is the system? He said, I don't know what is the system. It must exist and we are going to discover it. So we really started from scratch. And you'll see in a minute how people start from scratch. And I like the idea of starting from scratch because we really had no clue.
30:20
And to start from scratch at the time that there is no genetics, and it's not too long ago, you know, people think that they were born into genetics, but at that time there was no genetics. There was yeast genetics, yes, and some elegance genetics, but no mammalian genetics. No siRNA, no antisense, no knock-in, no fluxing, no nothing. We had to use nature, and nature provided us
30:41
with a wonderful cell. And this cell is the reticulocyte. It's the maturing red blood cell in the bone marrow. And you can induce lots of reticulocytosis. Avram is a physician, I'm a physician myself, so we knew that patients with anemia have reticulocytosis in the peripheral blood. So all what you do, you induce anemia in the rabbit, and the bone marrow pours tons of reticulocytes
31:03
into the circulation. And the beauty of the reticulocyte is that it doesn't have lysosome. We needed a cell without a lysosome because proteases are very sneaky, nasty enzymes. They will degrade everything around, and you need to work without a background. And we needed to work without the background of lysosomal proteases, and we used the reticulocytes,
31:23
and in no time we published the first paper in a very awkward journal, which is another lesson that journals really don't matter these days. This paper is cited more than 3,000 times. It came out in BBRC, and it became probably not only the first, but the most important paper in the history of the field
31:42
that now has close to 100,000 papers. So in this paper what we found is the following. We found exactly what we wanted. We found that high-speed supernatant, the extract of the cell, has an ATP-dependent activity that degrades globin. We use globin as an artificial subset. It doesn't matter. Later on we expanded the preparatory
32:02
of our substrate enormously. We just chose it. And there was another very important lesson in this, and I will not take you through biochemistry at all during the lecture because I want to pop quickly into medicine. We had here two fractions. So we took the lysate and we fractionated it biochemically, and none of the fraction
32:22
had an activity of its own, but we had to recombine them in order to get the activity. And this was a very fruitful lesson because it was also a shift from a paradigm. The paradigm in the field was that you need a protease and you need a substrate. So you need for this wedding two. Only two you need for this tango. And here we needed three. Two fractions, one and two, and the substrate.
32:41
So since these are crude fractions, if you need three, if you need two fractions, maybe you need 20 because these are crude fractions, and maybe you need 200. All I can tell you is the following. That modern biology via discovery via unraveling of the human genome showed that the ubiquitin system is composed of 1,500 enzymes.
33:02
They're not needed altogether for degrading every protein, but altogether it's the largest known family in the human genome. Once it's seven or eight percent of the total human genome, depends how you look at the genome. People look at the genome as having only 20. The human genome is having only 22,000
33:21
and several hundred proteins. We are not talking splicing products, T-cell receptors and antibodies into a calculation, but real hardcore proteins. Seven percent of the total human genome is occupied by one system. So the hint was already here, though we couldn't predict. Now let's go to what we really found.
33:41
And what we really found is something that was, again, a change in the paradigm. I will not go into the details. What we found is that in order to destroy a protein, we need first to tag it. We need to put on it some kind of a tag and the downstream proteins will not recognize the untagged protein.
34:01
So it's a two-step mechanism. Tagging, like you can imagine that it's the court system in democracies. So we don't catch criminals in the street and shoot them. We take them to the court, the court decide, and then we execute it, the punishment. So it's a two-step process. Now, I don't bring this metaphor just for the humoristic part of it,
34:22
but I bring this metaphor because it's enabled now scientists to explain how the protease and the substrate can live peacefully in the same compartment, which is the cytosol. Because proteases, active protease can never live with substrate in the same compartment. In the gastrointestinal tract, we don't care. We eat lunch, we want it to be digested.
34:41
So we don't care. In the circulation, we do care. We activate the protease only when we need it. So when we get wounded, we activate the blood coagulation system. We don't need the blood coagulation system to be active before. It will be deleterious, horrendous, if we shall get coagulation during the normal circulation.
35:01
I can bring you, it's a whole course in hematology what happens. So, and the lysosome also gave people this kind of thinking, relaxed thinking that the problem is solved because the lysosome has a membrane. So the problem was for the subset to get through the membrane. But the lysosomal proteases never see the substrate.
35:22
The substrate has to reach to the proteases. And here, for the first time, we provided a novel form of post-translational modification, tagging, by a protein called APF1, later on turned out to be ubiquitin, doesn't matter, I will not go to the history, that only subsets that are tagged are being degraded by a protease
35:42
that we now know is called the proteosome and actually it's a huge structure that I will tell you in a minute. It became a drug target and so on and so forth. So it's a tagging mechanism. We take a protein and the tagging, the subset to be degraded and the tagging protein and we make a conjugate.
36:01
We tag it and only then the protease come and releases amino acids. And then the tag recycles back into the system. So that's, and we knew it already in 1980. So this was a complete novel idea. We'll go into the details a little bit more because we need to understand them for understanding their diseases. So this is the tagging. Again, we should not go into the chemistry,
36:20
into the detailed chemistry. This is the subset, subset have lysine residues. The lysine residue by nature has an epsilon amino group and we are generating this very strange post-translational modification. It's a new protein that is bifurcated. People never heard of proteins that becomes tagged by other proteins and they look like a fork.
36:40
So you see here, this is the handle and this is the fork. So this is the victim to be degraded and now the protein comes and tags it. But it doesn't come once, it comes several times. And I'll show you how it comes. It comes several times, it come once. So this is the first tagging.
37:01
And then the first tagging protein become tagged himself by the second one. And then it goes to the third time. So the second is being tagged by the third. And we are building what we call a polyubiquitin chain. So the tag is not a simple unit tag, it's a polytag.
37:20
And the protease will recognize only the polytag. So this was a whole new thing for biologists that was very hard for them to accept and for us to decipher, but nevertheless, it went through and the protease, which is the 26th protozoan, will recognize only this behemoths. And will never recognize just the naked untagged substrate,
37:42
which again allowed the shark and the bait to live peacefully in the same very compartment, which was the essence of the whole system and which explained the specificity now and not only that, by understanding this tagging mechanism, we took the problem upstream. Because until then, the problem was who is the protease?
38:02
What is the mechanism? Now the problem is not the protease. The problem is who is the one to be tagged when, why, and where? So the problem moved upstream along the system to a complete different level of thinking. So there were many lessons in this type and the protease is important,
38:20
but the protease will do the same for all the tagged proteins. It will take every protein that is tagged by ubiquitin and degraded. So in that sense, maybe it's less interesting. It's still extremely interesting. Don't take me by the word, but the problem of specificity and recognition moved up. Who will be tagged by whom, when, where, and why?
38:42
So this is the modern ubiquitin system and then just show you in a snapshot and then we'll go quickly to medicine. So here is the substrate. So this is the target. It's like, I drew it like a wool ball. And in this case, it has to be phosphorylated because this is again, substrate are not just degraded.
39:01
They have to undergo something in order to be recognized. In this case, it will be phosphorylation and it will be recognized by an enzyme called ubiquitin ligase. Ubiquitin ligase, why? Because it like gates the tag to the substrate. And there are thousands of these in the database. Thousand ubiquitin ligases are sitting in the database
39:20
waiting for their different substrate. In parallel, ubiquitin will approach E1. There is only single E1 in the database, in the human genome. Ubiquitin will be activated by E1. It's called ubiquitin activating enzyme. Will be transferred. It's like a chain reaction. There are some reasons for this attenuation
39:41
in energy transfer. I will not go into it in determining specificity. To an E2, which is called ubiquitin carrier protein and there are about 50 E2s in the database. And then, bang. So the tag will be there. So the protein is now doomed to die, but it's not dead yet. And it's still reversible. We can still take this one away.
40:01
There is still a possibility along the chain to take this one away. So the system is flexible. It still didn't make the cut because if we put one cut into the protein, the protein is dead. We cannot glue it again. We have to go back via the entire synthetic machinery. And now comes the big beast, the 26S proteasome. We bind the chain.
40:21
We unfold the protein. And we take it in and spit it out in pieces. So that's basically the system. And the core part is recognition. This is the most important part of the system.
40:40
That's it. The binding, the recognition between the ligands because this initiates the entire chain. So this is the system. Now the system is hierarchical, as I told you. And that's very important to understand for medicine. There is a single E1, 50E2s, 1,000E3s. And each E3 will recognize a very limited subset
41:02
of substrates and will polyubiquitinate them. And then the proteasome will sit here. So then you can imagine that the system is diamond shaped, tapered at the top, tapered at the bottom, wide at the middle. Now, immediately, if you want to drag the system to use it as a drug platform, you will immediately want to do it here
41:21
in the broadest point. Why? Because it's the most specific point. You don't cause side effects and so on and so forth. So no doubt that this is the point to go, but it's not simple to go into this point and we'll evolve this idea of drugability of the system and how it's related to diseases in the next few minutes. Meanwhile, what happened is a very enriching development
41:41
that we were not involved in it at all. We were pushed to the side completely. We were almost forgotten. And ubiquitin is a degradation signal became just one function of ubiquitin. So we are here now. With our discovery, E1, E2, E3, polyubiquitination, protosome degradation. But then the world became much richer
42:02
and people discovered ubiquitinide proteins. So Frauke Melchior, who now happens to be here in the university, when she was a postdoc with Larry Gerace in San Diego, discovered SUOMO, which is small ubiquitin modifier. And it's a ubiquitinide protein that is activated like ubiquitin, but it modifies protein only once
42:20
and it helps this green protein find its destination to the nuclear pore complex. Otherwise, this green one will wander in the cell and will not know where to go. And it's a major problem in the cell. The cell has heavy traffic. There is no GPS in the cell. So we have to provide all the proteins with GPS, small GPS machines, so they will know where to go. And this SUOMO is a kind of a mini GPS
42:42
for this green protein to go here. And cell surface membrane proteins are oligoubiquitinated and then they go to the lysosome. And ubiquitin itself has several lysins, as I told you. Ubiquitin is ubiquitinated himself, itself on a lysin residue, which is lysin 48,
43:02
but it has seven lysins and we can build different chains. So the change that, what we got now basically without going into details, and here there is monoubiquitination. So we can go to polyubiquitination, we can go to oligo and we can go to mono and we can go to SUOMO elation, which is other proteins. And we are now in a huge world
43:21
of novel form of post-translational modification that is extremely rich because it's made by a protein. And as you know, proteins have lots of variability. We have their family members and likes and it allowed the system to acquire huge flexibility. So if about 10 years ago I would have been asked what is ubiquitin, I would have said
43:40
ubiquitin is a degradation signal. Now I would say that ubiquitin is a passport. A passport is a document that allows different passengers to go to different destinations. So if it's a certain polyubiquitination, it's a passport to the proteasome. It's a different polyubiquitination, it's a passport for activation of transcription. NF kappa B is activated by polyubiquitination
44:01
by different chains, so the chains are very different. SUOMO is a passport to the Rang B to go to the nuclear pore complex. And BRCA1, which is a very important protein, is involved in breast cancer tendency in women. BRCA1 is ubiquitinated, is a ubiquitin ligase
44:24
that ubiquitinates funcone protein, which is involved in funcone anemia. It is another malignant, inherited malignant disease. So it's, ubiquitination serves many, many different functions in the cell and degradation is just one of this many. So we became a member, we thought that we are the family
44:42
but we went wrong, we are just members of a large family. We are not the family. Now let's go quickly to diseases. And this is the development of the last 10 or 12 years and it's a fascinating development. So normally we can imagine that this, and now going into the diseases, I will again focus only on proteolysis
45:02
because the other members of the family are still young and haven't said their final word yet. But they clearly are going to be targeted and I can imagine, I know also, I'm on several scientific advisory boards of companies, people will target the other functions. But let's go back just to proteolysis. So this is the ubiquitin system, just a scheme and proteins are degraded and they are in a steady state,
45:22
whatever, can be static steady state, dynamic steady state, but they are keeping their green box. Now two problems can occur. Either protein will be over degraded, so it will go below the steady state and this can happen, let's say, that a ligase is going up in an uncontrolled manner. The ubiquitin ligase that ubiquitinates the protein
45:40
will all of a sudden be expressed in uncontrolled manner and will take a protein down. And I'll show you one very prevalent example. Or something can happen here and the ligase will be mutated or the substitute will be mutated and the protein will accumulate. So both cases have happened and let's take cancer as a case of study.
46:00
Because cancer has been really extensively studied as a model for the ubiquitin system and actually the first drugs, the one that is in the market, the one that will be soon in the market are all cancer drugs. So again, but we have again, I want really to understand first with you concepts. So different diseases result from aberrations,
46:21
ubiquitin with degradation of different groups of proteins. If there will be a problem with quality control, if we shall not, this is typically a problem of under degradation. If we don't degrade proteins that should be degraded, they accumulate. Aberration and degradation of quality control will typically lead to neurodegenerative diseases as we know them now.
46:41
And to some accumulation diseases in the liver, malory bodies diseases and so on. But mostly the quality control will belong to the brain and we see that the hallmark of many neurodegenerative diseases, either genetically acquired or sporadic late onset diseases is accumulation of some types of proteins.
47:00
Not always related to the ubiquitin system, but many are. While if we are losing control of processes it will mostly end with cancer. Because it will typically will be an oncogene that is activated and not degraded and so on. It will be typically one protein. And let's leave a differentiation and more for genesis, will typically lead to genetically diseases. But I want mostly to talk about these two groups.
47:23
So let's go, and this is obviously one example of brains taken from patients that have some aberration in the ubiquitin system, some transcript of the ubiquitin system and they suffer Alzheimer's disease. But let's go to cancer.
47:41
Because cancer will be much easier to understand. So if there will be an increased degradation of a tumor suppressor like P53, there will be cancer. Because the cell will be exposed to a damage. P53 is the ultimate genome guardian. It's a sensor basically. You know we are in an era
48:01
in which we are talking the language of sensors. We are interested in sensors. And P53 is the ultimate damage sensor. There will be a damage to the cell, the sensor will jump up, will stop cell cycle, will try to repair the damage and if the damage will not be repaired, the sensor will kill the cell. Will send it to apoptosis. And P53 has been associated now one way or another
48:21
with almost 80 or 90% of all cancers. It is mutated in 50% and it's normal in 30% but then its metabolism is aberrated in this 30%. So P53 is a critical molecule. So obviously, hyperdegradation of P53 will lead to cancer. And I can give you two examples.
48:40
Real example, one is the human papilloma virus that leads to uterine cervical carcinoma in women. And this is a virus that is directly associated with this malignancy. And this virus encodes an oncogene called E6. The E6 combines to P53, generates a heterodimer with P53. The ubiquitin system
49:00
that is a quality control system misleads to think that this P53 is aberrant because it's now heterodimerized with another foreign protein and will jump on the system and degrade it. And it will degrade it in an aberrant manner using a ligase that will never recognize P53. Actually this ligase is a very interesting ligase from a neurological point of view. It's called E6AP or E6 associated protein
49:23
because it acts with E6 to degrade P53. But we can imagine that God or whoever was in charge of evolution, depends on our view, personal view, did not evolve E6AP in order to degrade, did not evolve E6AP in order to degrade P53
49:42
and to cause woman damage. We cannot suspect our creator to be that bad or that malicious. So E6AP was created for something else completely. And people describe the aberration, what happens with E6AP. E6AP is a protein that once aberrated, leads to a very severe genetic neurological syndrome
50:03
called Engelmann syndrome. The kids are born with a severe mental retardation. They have a severe neurological syndrome. They are walking on a white gate. They laugh out of context. And so the idea with this disease is, and it's a close relative of another,
50:22
another disease in which people have increased appetite. It's called Prader-Willi syndrome. And it's closely linked to it. Genetically, I will not go into the... So the idea with the Engelmann syndrome, with this mental retardation, is that you have a defect in a ligase that was built for some other substrate. Since the ligase is defective,
50:41
some protein accumulates, and this protein is neurotoxic. And the end of this neurotoxicity is the Engelmann syndrome. And it happens so that the viruses, which are very smart, adopted E6AP also to remove P53 during HPV, human papillomavirus, infection of the uterine endothelium, cervical endothelium.
51:01
So it's very interesting kind of complex linkage. Now, so this is P53. It's being degraded. There is no genome guardian, and the virus can integrate into the DNA and go to transformation. The opposite is an oncogenic protein. Now, oncogenic protein are normal proteins.
51:20
I mean, all growth-promoting proteins in the body have potential to become oncogenic if overactive. So take beta-catenin that acts in our intestine. Once it's becoming overactive, it's not degraded, it will induce colorectal carcinoma. Take the EGF receptor, that once truncated and overactive, it's not regulated anymore,
51:41
will lead to on and on and on signaling, and at the end, will lead to breast cancer. So this is the famous herin-neu cancer. Some of them are susceptible to herceptin, to the new antibody. So either under degradation of oncogenic protein or over degradation of a tumor suppressor, will lead to cancer.
52:01
So we don't have now to go into examples. I think that we really need to understand. Now let's go to drugs. I want to conclude the talk by telling you that we are dealing not with theories. We are dealing with real patients. So the best place to put the drug will be here, as I told you, but the first drug was not developed to this point. The first drug, surprisingly, was developed to the proteasome for many reasons.
52:22
I don't want to go into the reasons. First of all, it was very easy. The proteasome is a protease at the end. So it's very easy to develop drugs, protease inhibitors. There are many in the market. They have been before. People know exactly the structure of the active sites of proteases, and it was very easy. All what they had to do
52:40
is to make it specific to the proteasome. So to take a relatively non-specific small molecules and to make it high efficiently, highly efficient, high affinity, highly specific. And that's what the company did. It's a Boston-based company. I have nothing to do with the company. It's a late development. And the drug is called PS341 or Valkade or bortezomib.
53:03
Well used now. It was approved by the FDA three years ago, and it's heavily used now in many cancers, and in one in particular that I'm going to show you. It's a simple peptide, you see, with a boronic acid derivative, and it nucleophilically attacks the active threonine residue in the active site of the protein.
53:21
So the mechanism is well worked out molecularly, and we know exactly what the drug is doing at the molecular level. And here is the patient. This is the drug. And here is the patient with multiple myeloma, just for those of you who are not talking medicine daily. Multiple myeloma is a type of leukemia. So it's a monocellular expansion.
53:40
One cell becomes malignant. It's plasma cell. The plasma cells are the cells in our bodies that generate antibodies. But we have different plasma cells. We have zillion of plasma cells that encompass, that constitute the entire immunologic repertoire. Basically we can immunize ourselves against every single potential antigen.
54:01
Let it be some plant, some extract from plants in Australia that we've never been exposed to. Whatever antigen. That's the beautiful work of Medawar and Barnett that got the Nobel Prize in the 60s. Unbelievable. Beautiful work. But in this case it's cancer. So it's one plasma cell
54:21
expands in an uncontrolled manner. And this one plasma cell can secrete one single immunoglobulin in this patient. It's a woman. It can secrete IgA. Now the beauty of this disease, not for the patient, the patient is dying. The beauty of this disease, and that's the dream of every oncologist and physician, that this antibody is a biomarker.
54:41
So we can take a small sample of the blood and look to the biomarker. And the more we have, the worse is the situation of the patient. The less we have, the more suppressed is the tumor. But very few tumors unfortunately, handful or less, are secreting such wonderful biomarkers. It's the dream now of modern mass spectrometries
55:01
and high protein resolution is to find in the blood biomarkers for different cancers. But we need very, very sensitive detection systems like we need for everything. We are still away from this. So here you can see the disease is galloping. Here started the regular chemotherapy, Melphalan, Adriamycin, Decadron,
55:22
whatever the physis, the oncologists know how to poison the patient. And the disease responds partially. And then the disease relapses again and here started a treatment with PS341. And the disease recedes. And it's not a miracle. I mean, this is a rare patient. I mean, not all patients respond
55:40
and the question will be who are the responders and whatnot. But it's no doubt a revolution in treatment of this disease. This is a deadly disease. Patients are dying in agony in two to three years because the bone marrow is taken completely by the plasma cells. So all the other blood progenitors are gone. They are suffering infections, coagulation problems because of lack of
56:01
thrombocytes, megakaryocytes are not there. And then the bones are being broken because the tumor presses against the bone and the bone marrow fractures in the vertebrae, fractures in the long bones because of this protein renal insufficiency. It occludes the tubuli in the kidneys.
56:23
It's a very bad disease, very bad disease. And here the patient responds and here you can see bone marrow of the patient. And again, without going into oncologic histopathology, you can see the major difference between the homogeneous malignant bone marrow before the treatment and the almost normal bone marrow, the cells,
56:42
the malignant cells went down from 41 to less than 1%, which is now repopulated with a normal bone marrow progenitors, the red and the white blood cells. So you see that the patient is being helped and the patient is still in remission. So very few patients go into remission that lasts for many years. Here is another patient. This is a CAT scan of the chest
57:04
and you can see a tumor sitting here. This is a non-Hodgkin lymphoma, a tumor sitting here in the right hill, in the hill of the right lung and the tumor recedes by an order of magnitude after a single cycle. Now, since the drug comes from a different world, it's not a chemotherapy. In combination with chemotherapy and radiotherapy,
57:22
it's extremely efficient and the indications are broadened, I wouldn't say daily, but every month I see a new paper coming in the New England in cancer research in the journal of the NCI of a new indication. So ovarian cancer, it was completely resistant to any treatment. Again, a deadly disease is now being treated successfully.
57:42
Again, not all cases. We have to be very cautious. I'm not here to advertise or to spread any hopes, but it's a new approach to oncology because it's coming from, not from the DNA chelating agent, not from Adriamycin and Doxorubicin and irradiation. It's coming from a different system and therefore it hopes by itself
58:02
and with combination a new hope. But the future now, let's go to the last section. The future is in new drugs. It's not in protozoan inhibitors. It's in ligase inhibitors and I want to go back to p53 because it's really an attractive molecule. So as I told you, every stress to the cell, DNA damage, telomere shortening, oncogene activation
58:23
will lead immediately to increase in p53 and p53 will act along timeline. It's a very important protein, as I told you, to do three activities in a timeline. Immediately it will stop the cell cycle because the cell cannot proceed to division
58:41
with a damage. It will attempt DNA repair and if not, it will induce apoptosis. Let's leave alone senescence. It has to do with p16 and polycomb complexes. That's much more complicated. I don't want to go into it. But in order, growth arrest, DNA repair and if not, death.
59:00
Now, so that's basically p53. Oncogenic stress will elicit p53 to inhibit cancer. We can simplify it and this simplistic scheme is basically correct. Now, normally p53 cycles with its own ubiquitin ligase. It's very interesting. So p53 is a transcription factor.
59:20
It transcribes many downstream genes. One of the genes that it transcribes is its own executioner. So once the executioner is up, p53 will be down. It will be degraded. Now, once p53 is degraded, it will not be able to transcribe the executioner. So the executioner will be down. Then p53 will be up again and this will be up and this will be down.
59:41
So we cycle and people measure indeed there are oscillations between p53 and its own executioner. Very simple servo loop mechanism. Simple oscillation and that occurs all the time. Now, once there is oncogenic stress, something happens. p53 undergoes phosphorylation.
01:00:00
and acetylation and becomes resistant to the HDM2 and then it goes up because the HDM2 will also go up but it will not affect p53 anymore because p53, there will be an aberration in recognition. The acetylation and phosphorylation will abrogate the recognition and this will
01:00:22
allow p53 now to act and to activate the downstream gene, to arrest cell cycle, to elicit DNA repair and to induce apoptosis if necessary. So this is part of the oncogenic stress that immediately upon induction of a stress p53 must become resistant to its ligus, to the execution so it will be able to go up and
01:00:45
to do what it wants because otherwise it will be degraded. So this is part of the normal response. Now in cancer, in some of the cancers, well a lot of the cancers, 30% or 25% of all cancers, something very bad happens and the ubiquitin ligase stops to respond, the HDM2, the ligase
01:01:05
of p53 stops to respond to the oscillating control mechanism and it goes up and doesn't care about anything, it just over-expressed. If it's over-expressed, it will bring p53 down so p53 will not be able to act once needed
01:01:22
and because there is so much of the HDM2 that it will basically suppress everything and the acetylation and the phosphorylation process will not be efficient anymore in light of this ocean of MDM2, I don't want to go into it because it has to do with quantity of how much of the p53 is being, but that's basically what happened.
01:01:42
Basically the ligase has become an oncogene. By what? By turning down a tumor suppressor. So ideally, if we shall be able to inhibit this interaction, so HDM2 will still go up, well it's down here by activity, but we shall be able to inhibit the activity of MDM2
01:02:03
over p53, we shall rescue the system. So all that is needed from the company, from a company, is to develop a small molecule that inhibit this enzyme, specific inhibitor. So the enzyme can be high, but it will be inactive. And that's exactly what Roche is doing. They develop protein, a small molecule called nutlin, called nutlin because it was developed
01:02:25
in Nutlin, New Jersey, where the headquarters of the company is. And what nutlin is doing, it's a modern drug. It's not a drug that came out of high throughput assays. It's a drug that came out of modern biology, of understanding the three-dimensional structure of a protein.
01:02:41
This is MDM2, this is the pocket that binds p53. And nutlin was planned to occupy the pocket. So it's a specific inhibitor that competes out p53 and will not let it go there. So it's a very specific small molecule inhibitor. And here you can see the result, and that will be almost the very end.
01:03:03
So we add nutlin, p53 is induced. p53 is inducing also its own executioner, but the executioner cannot kill p53 because the executioner is a dead one. Because nutlin is always around to inhibit it. And the fact is that p53 can induce very effective cell cycle inhibitor called p21.
01:03:23
So it's an active p53. And though the executioner is around, it's a dead executioner. And the result, that 50% or 45% of the cells that used to cycle, that were in the S and presence of nutlin are out, 5% only. So they don't synthesize DNA anymore and they're going to rest.
01:03:42
So we move them from the S phase into the G1 or even G0 phase of the cell cycle. And the result in mice, these are skid mice. Here is the tumor that grows, a control tumor that grows. And treatment with nutlin, exactly like treatment with doxorubicin,
01:04:01
which is a DNA chelating, highly toxic, cardiotoxic agent have the same effect. They inhibit the growth of the tumor. So what we see now is a shift from nonspecific drugs that inhibit the proteasome into a very specific drug that can inhibit and block a very specific pathway.
01:04:24
And I believe that this will be the future of the system. So just to thank the people and before I'm thanking the people, I will not go over the list obviously, just point out some important. It's just to tell you that about less than 30 years ago,
01:04:41
actually exactly 30 years ago, I started my PhD in October of 76. I started with a mentor that had no idea where he goes. He couldn't define a system. And I think that about five years ago it was a turning point when the first drug was approved and we are now in a completely different era.
01:05:01
So you see how things are evolving. But we shouldn't take all the credit. We shouldn't take half of the credit. We shouldn't take even a quarter of the credit. We added a layer of understanding. But basically we knew when we entered the field that proteins are degraded. That's Schoenheimer. We knew that it requires energy. That's Simpson. We knew that it's not the lysosome.
01:05:21
That's Brian Poole. And all what we did, we collected all this information and we concluded that there must be something else and we went into the something else. And then other people came and added this information. And I think that the entire pathway, if you really want to be fair to the system, took about 70 years to get to the point. And we played a role somewhere in the late 70s and early 80s and added our own layer.
01:05:45
And just to thank obviously Avram and Ernie. Avram was my direct mentor. Ernie played an extremely important role in the middle. He really deciphered the type of bond that ubiquitin is making. And the polyubiquitin chain, we had no clue. So physicians know about reticulocytes, but they have no clue of protein chemistry.
01:06:04
We needed a good protein chemist in the middle to unplot this gem for us. And then I enjoyed an extremely fruitful period at Harvey's lab. Basically he's not only a good scientist that helped me a lot with my question,
01:06:22
but he gave me complete freedom. I mean I was completely free to do what I wanted. And at that time I collaborated with Alex Varshavski and Daniel Finley at MIT. And we found the first mutant of the ubiquitin system because this was important to show that the system is not limited to the reticulocyte. But it's rather universal. So it wasn't a breakthrough, but it was a further important corroboration of the concept.
01:06:44
So this was a very fruitful time. I was a postdoc in one lab, collaborated with another lab, and was able to move freely along the MIT corridors, which was wonderful. And then many, many postdocs and graduate students, some of them are still there and keeping on my lab active.
01:07:01
So thank you very much.
01:07:26
So thank you very, very much for this wonderful and fascinating lecture. I have a small book and it contains kind of the honorable persons here in Gottingen who lived and studied here. So it's a little book about the Nobel Prize winners,
01:07:41
which stopped by at least here, not you included. And thanks again for this lecture. I must say, you did not mention, of course, the other part of the UPS system, which now comes into our mind. And this is the protein aggregation disorders, which we have to face. So this will be the future. You addressed the kind of easy part, which is cancer treatment.
01:08:03
Now we have to use your help in order to address the more complicated ones, and that is to treat, today is the Alzheimer's Day, I forgot to mention, to treat the aggregation disorders, which will be coming up once the people do not die from cancer anymore. So thanks again very much for this wonderful lecture
01:08:22
and for coming to Gottingen. Thank you.