PMID- 10329681
OWN - NLM
STAT- MEDLINE
DCOM- 19990709
LR  - 20210209
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 274
IP  - 21
DP  - 1999 May 21
TI  - Identification of the ubiquitin carrier proteins, E2s, involved in signal-induced
      conjugation and subsequent degradation of IkappaBalpha.
PG  - 14823-30
AB  - The last step in the activation of the transcription factor NF-kappaB is
      signal-induced, ubiquitin- and proteasome-mediated degradation of the inhibitor
      IkappaBalpha. Although most of the components involved in the activation and
      degradation pathways have been identified, the ubiquitin carrier proteins (E2)
      have remained elusive. Here we show that the two highly homologous members of the
      UBCH5 family, UBCH5b and UBCH5c, and CDC34/UBC3, the mammalian homolog of yeast
      Cdc34/Ubc3, are the E2 enzymes involved in the process. The conjugation reaction 
      they catalyze in vitro is specific, as they do not recognize the S32A,S36A mutant
      species of IkappaBalpha that cannot be phosphorylated and conjugated following an
      extracellular signal. Furthermore, the reaction is specifically inhibited by a
      doubly phosphorylated peptide that spans the ubiquitin ligase recognition domain 
      of the inhibitor. Cys-to-Ala mutant species of the enzymes that cannot bind
      ubiquitin inhibit tumor necrosis factor alpha-induced degradation of the
      inhibitor in vivo. Not surprisingly, they have a similar effect in a cell-free
      system as well. Although it is clear that the E2 enzymes are not entirely
      specific to IkappaBalpha, they are also not involved in the conjugation and
      degradation of the bulk of cellular proteins, thus exhibiting some degree of
      specificity that is mediated probably via their association with a defined subset
      of ubiquitin-protein ligases. The mechanisms that underlie the involvement of two
      different E2 species in IkappaBalpha conjugation are not clear at present. It is 
      possible that different conjugating machineries operate under different
      physiological conditions or in different cells.
FAU - Gonen, H
AU  - Gonen H
AD  - Department of Biochemistry and the Rappaport Family Institute for Research in the
      Medical Sciences, Bruce Rappaport Faculty of Medicine, Haifa 31096, Israel.
FAU - Bercovich, B
AU  - Bercovich B
FAU - Orian, A
AU  - Orian A
FAU - Carrano, A
AU  - Carrano A
FAU - Takizawa, C
AU  - Takizawa C
FAU - Yamanaka, K
AU  - Yamanaka K
FAU - Pagano, M
AU  - Pagano M
FAU - Iwai, K
AU  - Iwai K
FAU - Ciechanover, A
AU  - Ciechanover A
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Carrier Proteins)
RN  - 0 (DNA-Binding Proteins)
RN  - 0 (I-kappa B Proteins)
RN  - 0 (NF-kappa B)
RN  - 0 (NFKBIA protein, human)
RN  - 0 (Ubiquitins)
RN  - 0 (ubiquitin carrier proteins)
RN  - 139874-52-5 (NF-KappaB Inhibitor alpha)
RN  - EC 2.3.2.23 (Ubiquitin-Conjugating Enzymes)
RN  - EC 6.- (Ligases)
SB  - IM
MH  - Carrier Proteins/genetics/*isolation & purification/physiology
MH  - DNA-Binding Proteins/*metabolism
MH  - HeLa Cells
MH  - Humans
MH  - *I-kappa B Proteins
MH  - *Ligases
MH  - Mutation
MH  - NF-KappaB Inhibitor alpha
MH  - NF-kappa B/*antagonists & inhibitors
MH  - Phosphorylation
MH  - Second Messenger Systems
MH  - Species Specificity
MH  - *Ubiquitin-Conjugating Enzymes
MH  - Ubiquitins/genetics/*isolation & purification/physiology
EDAT- 1999/05/18 00:00
MHDA- 1999/05/18 00:01
CRDT- 1999/05/18 00:00
PHST- 1999/05/18 00:00 [pubmed]
PHST- 1999/05/18 00:01 [medline]
PHST- 1999/05/18 00:00 [entrez]
AID - 10.1074/jbc.274.21.14823 [doi]
AID - S0021-9258(19)73162-7 [pii]
PST - ppublish
SO  - J Biol Chem. 1999 May 21;274(21):14823-30. doi: 10.1074/jbc.274.21.14823.