Journal Article

cIAP1/2 Are Direct E3 Ligases Conjugating Diverse Types of Ubiquitin Chains to Receptor Interacting Proteins Kinases 1 to 4 (RIP1–4)

Bertrand, Mathieu J. M., Roelandt, Ria, De Medts, Jelle, Lippens, Saskia, Staes, An, Vandenabeele, Peter, Gevaert, Kris, Declercq, Wim, Gilbert, Barbara

2011

Overview

The RIP kinases have emerged as essential mediators of cellular stress that integrate both extracellular stimuli emanating from various cell-surface receptors and signals coming from intracellular pattern recognition receptors. The molecular mechanisms regulating the ability of the RIP proteins to transduce the stress signals remain poorly understood, but seem to rely only partially on their kinase activities. Recent studies on RIP1 and RIP2 have highlighted the importance of ubiquitination as a key process regulating their capacity to activate downstream signaling pathways. In this study, we found that XIAP, cIAP1 and cIAP2 not only directly bind to RIP1 and RIP2 but also to RIP3 and RIP4. We show that cIAP1 and cIAP2 are direct E3 ubiquitin ligases for all four RIP proteins and that cIAP1 is capable of conjugating the RIPs with diverse types of ubiquitin chains, including linear chains. Consistently, we show that repressing cIAP1/2 levels affects the activation of NF-κB that is dependent on RIP1, -2, -3 and -4. Finally, we identified Lys51 and Lys145 of RIP4 as two critical residues for cIAP1-mediated ubiquitination and NF-κB activation.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Activation / Amino Acid Sequence / Apoptosis / Biochemistry / Biology / Biomedical research / Cell surface / Cellular stress response / Chains / HEK293 Cells / Humans / Inhibitor of Apoptosis Proteins - metabolism / Kinases / Ligases / Localization / Molecular biology / Molecular modelling / NF-kappa B - metabolism / NF-κB protein / Nuclear Pore Complex Proteins - metabolism / Pattern recognition / Pattern recognition receptors / Phosphorylation / Protein kinases / Proteins / Receptor-Interacting Protein Serine-Threonine Kinase 2 - metabolism / Receptor-Interacting Protein Serine-Threonine Kinases - metabolism / Receptors / RNA-Binding Proteins - metabolism / Signaling / Studies / Tumor necrosis factor-TNF / Ubiquitin / Ubiquitin - chemistry / Ubiquitin - metabolism / Ubiquitin-protein ligase / Ubiquitin-Protein Ligases - metabolism / Ubiquitination / X-Linked Inhibitor of Apoptosis Protein - metabolism / XIAP protein