The Nobel Prize in chemistry 2004

Ubiquitin(Ub)泛素

Class B Group 3黃恒橋、劉國正、黃偲媁黃竣聖、簡農軒、楊昆霖

Nobel Laureate

IsraelAaronCiechanover

IsraelAvramHershko

USA

Irwin

Rosehttp://big5.cctv.com/science/20041008/101027.shtml

The Discovery of The Ubiquitin

simple protein-degrading enzymes TrypsinLysosome

do not require energy

Traditional concept

Paradox 1950s － the breakdown of the cell's prot

eins require energy

The inhibitor of lysosome has no effect on some protein degradation

Rabbit reticulocytes ( 網織紅血球 ) degrade abnormal hemoglobin

The Discovery of The Ubiquitin

1975 － isolated Ub from sweetbread

( 小牛胸腺 ) 1977 － an extract from reticulocytes 1970s ～ 1980s － the extract could be

divided into two fractions Fxn1 Fxn2

The Discovery of The Ubiquitin

ATP-dependent proteolysis factor 1 (APF-1) 1981 ～ 1983 － enzyme systems that bin

ds ubiquitin to target proteins

multistep ubiquitin-tagging hypothesis

Poly Ub : Ub-proteasome pathway For protein (peptide) recyclingDecomposition( proteasome ) The kiss of death

Mono Ub: non-degradationModification(methylation of Histone)

The Function of Ubiquitin

Target protein

UbUb

Target protein

UbUbUbUbUbUb

The structure of Ubiquitin

A 76 a. a. protein Stable: O H Highly conserved Exist in archeabacte

ria and all eukaryotes

http://www.nottingham.ac.uk/biochemcourses/students/ub/ubindex.html

Binding

target proteinUb’s C-terminus the target protein’

s LysineForm isopeptide

target protein

Lysine

UbUb

Poly-ubiquitinization

Ub’s C-terminus Ub’s lysine Purpose: recognize diversity protein

Protein 1

Protein 2

UbUb UbUb

UbUb UbUbUbUbUbUb

UbUb

UbUb

Target protein

Target protein

L48 vs.L63

UbUbUbUbUbUbUbUb

UbUbUbUbUbUbUbUb

L48

L63

Degraded by proteasome

Degraded by lysosome

Met1-Gln2-Ile3-Phe4-Val5-Lys6-Thr7-Leu8-Thr9-Gly10-Lys11-Thr12-Ile13-Thr14-Leu15-Glu16-Val17-Glu18-Pro19-Ser20-Asp21-Thr22-Ile23-Glu24-Asn25-Val26-Lys27-Ala28-Lys29-Ile30-Gln31-Asp32-Lys33-Glu34-Gly35-Ile36-Pro37-Pro38-Asp39-Gln40-Gln41-Arg42-Leu43-Ile44-Phe45-Ala46-Gly47-Lys48-Gln49-Leu50-Glu51-Asp52-Gly53-Arg54-Thr55-Leu56-Ser57-Asp58-Tyr59-Asn60-Ile61-Gln62-Lys63-Glu64-Ser65-Thr66-Leu67-His68-Leu69-Val70-Leu71-Arg72-Leu73-Arg74-Gly75-Gly76

Other lysine site(human’s Ub )

Ub-Proteasome Pathway

http://www.bio-pro.de/imperia/md/images/grafiken/ubisystem_338x398.jpg

Ubiquitnation

Remarkable features The specificity of protein tagging is

mainly determined by E2, E3 steps

E1:Ub-activating enzymeE2:Ub-conjugating enzymeE3:Ub-ligase

E2

E1:Ub-activating enzyme

E1

AMP Ub

S-H

ATP

Ub adenylate CysteineAdenylation

C-terminus

Cysteine

Activation

E2:Ub-conjugating enzyme

E2

AMP

Ub adenylate

Ub Ub Ub

E1S-HNew

E3

1.Connection of polyUb

2.Elongation of Ub with E3

E3:Ub-ligase

Two types

E3s which do form thiol esters

with ubiquitin

E3s which do not form thiol esters with ubiquitin.

E3

E3

E3

E3

From:www.wormbook.org/.../ubiquitinpathways.html Recognition of the substrate

Proteasome

Barrel-like structure

Degrade ubiquinated protein

Use the energy of ATP

Structure

Core protease particle (CP)Catalytic area

Regulatory particle (RP)Ubquitin recogniti

onDeubiquitinATPase

http://www.bioscience.utah.edu/mb/mbFaculty/hill/hill.html

α

β

β

α

http://www.bio-pro.de/imperia/md/images/grafiken/ubisystem_338x398.jpg

Ubiquitin and p53

Tumor suppressor gene DNA repair Apoptosis

Cancer reason ： HPV

Human Papillomavirus Activate E6-AP(E3) to ubiquitinate p53 Few P53 Dysplasia

Medicine

LDP-341 (PS-341) Proscript invented in 1995 Inhibit ubiquitin function

Retain cyclinInhibit NF-kappa BProtein pressure

Spinocerebellar Atrophy( 小腦萎縮症 )

Background detail Cause of disease- geneSymptom

nervous system: cell death Behavior: paralysis

One of causes- ” inclusion bodies “( 包涵體 )

Proteins are combined by SUMO-1 SUMO(Small ubiquitin-like modifier)

SUMO( 類泛素 )

Small ubiquitin-like modifier Function: Modification

Proteins linked by Ub or SUMO could be recognized by cell and be sent to different organelles.

Threat

Abnormal SUMO In Spinocerebellar Atrophy

Abnormal proteinSUMO

Ub

Abnormal protein

SUMO

Abnormal protein

SUMOAbnormal protein

SUMO

Abnormal protein

SUMO

Finally cell death

Parkinson’s Disease( 帕金森氏症 )

Background detailCause of disease- geneSymptom

Nervous system: death of basal ganglia ( 基底核 )and substantia nigra ( 黑質 ) cell

Behavior: tremor ； rigidityDopamine( 多巴胺 )

Reason (related to ubiquitin)Abnormal α-synuclein geneAbnormal parkin(E3) gene

Abnormal α-synuclein proteinUb

Abnormal

α-synuclein gene

Abnormal

parkin(E3) gene

Finally cell death

Finally cell death

Abnormal parkin(E3)

Abnormal protein

Abnormal α-synuclein protein

UbAbnormal α-synuclein protein

Ub

Abnormal α-synuclein protein

Ub

E2

Ub

Take Home Messages

Ub target substrates for degradation, traffic, or modification. The well-known function is involving ubiquitin proteasome system(UPS).

Ubiquitination has to be aided by E1:activating UbE2:regulating poly-ubiquitinizationE3:recognition of substrates

Take Home Messages

Mechanism of P53,HPV, Spinocerebellar Atrophy and Parkinson’s Disease are all related to the ubquitination, especially the function of E3.