c-IAP1 and UbcH5 promote K11-linked polyubiquitination of RIP1 in TNF signalling.
Ubiquitin ligases are critical components of the ubiquitination process that determine substrate specificity and, in collaboration with E2 ubiquitin-conjugating enzymes, regulate the nature of polyubiquitin chains assembled on their substrates. Cellular inhibitor of apoptosis (c-IAP1 and c-IAP2) proteins are recruited to TNFR1-associated signalling complexes where they regulate receptor-stimulated NF-κB activation through their RING domain ubiquitin ligase activity. Using a directed yeast two-hybrid screen, we found several novel and previously identified E2 partners of IAP RING domains. Among these, the UbcH5 family of E2 enzymes are critical regulators of the stability of c-IAP1 protein following destabilizing stimuli such as TWEAK or CD40 signalling or IAP antagonists. We demonstrate that c-IAP1 and UbcH5 family promote K11-linked polyubiquitination of receptor-interacting protein 1 (RIP1) in vitro and in vivo. We further show that TNFα-stimulated NF-κB activation involves endogenous K11-linked ubiquitination of RIP1 within the TNFR1 signalling complex that is c-IAP1 and UbcH5 dependent. Lastly, NF-κB essential modifier efficiently binds K11-linked ubiquitin chains, suggesting that this ubiquitin linkage may have a signalling role in the activation of proliferative cellular pathways.
Department of Protein Engineering, Genentech, Inc., South San Francisco, CA 94080, USA.
Jasmin N
JN
Dynek
Tatiana
T
Goncharov
Erin C
EC
Dueber
Anna V
AV
Fedorova
Anita
A
Izrael-Tomasevic
Lilian
L
Phu
Elizabeth
E
Helgason
Wayne J
WJ
Fairbrother
Kurt
K
Deshayes
Donald S
DS
Kirkpatrick
Domagoj
D
Vucic
D002460:Cell Line; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000378:metabolism*; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism*; D054875:Ubiquitination
C119724:AGFG1 protein, human; D051034:Inhibitor of Apoptosis Proteins; D016328:NF-kappa B; D028861:Nuclear Pore Complex Proteins; D016601:RNA-Binding Proteins; D014409:Tumor Necrosis Factor-alpha; D044763:Ubiquitin-Conjugating Enzymes