Document Detail


IRAK-4-dependent degradation of IRAK-1 is a negative feedback signal for TLR-mediated NF-kappaB activation.
MedLine Citation:
PMID:  18079163     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The activation of interleukin 1 receptor-associated kinase (IRAK)-1 is a key event in the transmission of signals from Toll-like receptors (TLRs). The catalytic activity of the protein kinase is not essential for its ability to activate nuclear factor (NF) kappaB, because transfection of a kinase-dead mutant of IRAK-1 (IRAK-1KD) is able to activate NF-kappaB in HEK293T cells. In the present study, we observed that the effect of IRAK-1KD was impaired by simultaneous expression of IRAK-4. The effect of IRAK-4 was accompanied by the phosphorylation and degradation of IRAK-1KD. Expression of IRAK-4KD instead of IRAK-4 did not cause these events. In IRAK-4-deficient Raw264.7 macrophages that were prepared by introducing short-hairpin RNA probes, the basal level of IRAK-1 was increased markedly. Stimulation of these cells with TLR ligands did not cause the degradation of IRAK-1, which was clearly observed in the parent cells. These results suggested that the expression of IRAK-4 alone is sufficient to cause the degradation of IRAK-1; the autophosphorylation of IRAK-1 is not necessary to terminate the TLR-induced activation of NF-kappaB. IRAK-4 has an ability to induce the degradation of IRAK-1 in addition to its role as an activator of IRAK-1.
Authors:
Miho Kubo-Murai; Kaoru Hazeki; Kiyomi Nigorikawa; Takatoshi Omoto; Norimitsu Inoue; Osamu Hazeki
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Publication Detail:
Type:  Journal Article     Date:  2007-12-13
Journal Detail:
Title:  Journal of biochemistry     Volume:  143     ISSN:  0021-924X     ISO Abbreviation:  J. Biochem.     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-03-03     Completed Date:  2008-06-23     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0376600     Medline TA:  J Biochem     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  295-302     Citation Subset:  IM    
Affiliation:
Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, Minami-ku, Hiroshima, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Line
Feedback, Physiological* / drug effects
Humans
I-kappa B Proteins / metabolism
Interleukin-1 Receptor-Associated Kinases / metabolism*
Lipopolysaccharides / pharmacology
Macrophages / drug effects,  metabolism
Mice
NF-kappa B / metabolism*
Protein Processing, Post-Translational* / drug effects
Signal Transduction* / drug effects
Toll-Like Receptor 4 / metabolism*
Chemical
Reg. No./Substance:
0/I-kappa B Proteins; 0/Lipopolysaccharides; 0/NF-kappa B; 0/Toll-Like Receptor 4; EC 2.7.1.37/IRAK1 protein, human; EC 2.7.11.1/Interleukin-1 Receptor-Associated Kinases

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