Activation of the Ikappa B kinases by RIP via IKKgamma /NEMO-mediated oligomerization.
To understand the mechanism of activation of the IkappaB kinase (IKK) complex in the tumor necrosis factor (TNF) receptor 1 pathway, we examined the possibility that oligomerization of the IKK complex triggered by ligand-induced trimerization of the TNF receptor 1 complex is responsible for activation of the IKKs. Gel filtration ... analysis of the IKK complex revealed that TNFalpha stimulation induces a large increase in the size of this complex, suggesting oligomerization. Substitution of the C-terminal region of IKKgamma, which interacts with RIP, with a truncated DR4 lacking its cytoplasmic death domain, produced a molecule that could induce IKK and NF-kappaB activation in cells in response to TRAIL. Enforced oligomerization of the N terminus of IKKgamma or truncated IKKalpha or IKKbeta lacking their serine-cluster domains can also induce IKK and NF-kappaB activation. These data suggest that IKKgamma functions as a signaling adaptor between the upstream regulators such as RIP and the IKKs and that oligomerization of the IKK complex by upstream regulators is a critical step in activation of this complex.
Mesh Terms:
Animals, Biopolymers, Cell Line, Enzyme Activation, Humans, I-kappa B Kinase, Phosphorylation, Protein-Serine-Threonine Kinases, Proteins, Receptor-Interacting Protein Serine-Threonine Kinases
Animals, Biopolymers, Cell Line, Enzyme Activation, Humans, I-kappa B Kinase, Phosphorylation, Protein-Serine-Threonine Kinases, Proteins, Receptor-Interacting Protein Serine-Threonine Kinases
J. Biol. Chem.
Date: Dec. 01, 2000
PubMed ID: 10980203
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