Interleukin-1 (IL-1) receptor-associated kinase leads to activation of TAK1 by inducing TAB2 translocation in the IL-1 signaling pathway.
Interleukin-1 (IL-1) is a proinflammatory cytokine that recognizes a surface receptor complex and generates multiple cellular responses. IL-1 stimulation activates the mitogen-activated protein kinase kinase kinase TAK1, which in turn mediates activation of c-Jun N-terminal kinase and NF-kappaB. TAB2 has previously been shown to interact with both TAK1 and TRAF6 and promote their association, thereby triggering subsequent IL-1 signaling events. The serine/threonine kinase IL-1 receptor-associated kinase (IRAK) also plays a role in IL-1 signaling, being recruited to the IL-1 receptor complex early in the signal cascade. In this report, we investigate the role of IRAK in the activation of TAK1. Genetic analysis reveals that IRAK is required for IL-1-induced activation of TAK1. We show that IL-1 stimulation induces the rapid but transient association of IRAK, TRAF6, TAB2, and TAK1. TAB2 is recruited to this complex following translocation from the membrane to the cytosol upon IL-1 stimulation. In IRAK-deficient cells, TAB2 translocation and its association with TRAF6 are abolished. These results suggest that IRAK regulates the redistribution of TAB2 upon IL-1 stimulation and facilitates the formation of a TRAF6-TAB2-TAK1 complex. Formation of this complex is an essential step in the activation of TAK1 in the IL-1 signaling pathway.
Department of Molecular Biology, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan.
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G
Takaesu
J
J
Ninomiya-Tsuji
S
S
Kishida
X
X
Li
G R
GR
Stark
K
K
Matsumoto
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000502:physiology*; D002460:Cell Line; D004789:Enzyme Activation; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology*; D020930:MAP Kinase Kinase Kinases / Q000502:physiology*; D020935:MAP Kinase Signaling System; D017472:Receptors, Interleukin-1 / Q000502:physiology*; D015398:Signal Transduction; D000099151:MAP Kinase Kinase Kinase 7
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D007375:Interleukin-1; D020930:MAP Kinase Kinase Kinases; D017472:Receptors, Interleukin-1; D000099151:MAP Kinase Kinase Kinase 7; C410585:TAB2 protein, human