1. Interleukin-1 Receptor-Associated Kinase-2 (IRAK2) Is a Critical Mediator of Endoplasmic Reticulum (ER) Stress Signaling
- Author
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Samir Benosman, Yasuko Matsuzawa, Ying Chen Hou, Renata Sano, John C. Reed, Muhammet F. Gulen, Shu-ichi Matsuzawa, Ricardo G. Correa, Minjia Yu, Xiaoxia Li, Paul Diaz, James A. Thomas, Palaniyandi Ravanan, and Michael Cuddy
- Subjects
Mouse ,lcsh:Medicine ,Gene Expression ,Biochemistry ,Mice ,RNA interference ,0302 clinical medicine ,Interleukin-1 Receptor-Associated Kinases ,Molecular Cell Biology ,Signaling in Cellular Processes ,RNA, Small Interfering ,lcsh:Science ,Apoptotic Signaling ,Cellular Stress Responses ,Mice, Knockout ,Transcription Factor CHOP ,Regulation of gene expression ,0303 health sciences ,Multidisciplinary ,Cell Death ,Animal Models ,Endoplasmic Reticulum Stress ,Cellular Structures ,Signaling Cascades ,Cell biology ,Nucleic acids ,Gene Knockdown Techniques ,030220 oncology & carcinogenesis ,Drosophila ,Signal transduction ,Signal Transduction ,Research Article ,Protein Serine-Threonine Kinases ,Biology ,Stress Signaling Cascade ,Cell Line ,03 medical and health sciences ,Model Organisms ,Animals ,Humans ,Gene silencing ,030304 developmental biology ,Sequence Homology, Amino Acid ,ATF6 ,Endoplasmic reticulum ,lcsh:R ,Membrane Proteins ,Gene Expression Regulation ,Subcellular Organelles ,Unfolded Protein Response ,Unfolded protein response ,RNA ,lcsh:Q - Abstract
Endoplasmic reticulum (ER) stress occurs when unfolded proteins accumulate in the lumen of the organelle, triggering signal transduction events that contribute either to cellular adaptation and recovery or alternatively to cellular dysfunction and death. ER stress has been implicated in numerous diseases. To identify novel modulators of ER stress, we undertook a siRNA library screen of the kinome, revealing Interleukin-1 Receptor-Associated Kinase-2 (IRAK2) as a contributor to unfolded protein response (UPR) signaling and ER stress-induced cell death. Knocking down expression of IRAK2 (but not IRAK1) in cultured mammalian cells suppresses ER stress-induced expression of the pro-apoptotic transcription factor CHOP and activation of stress kinases. Similarly, RNAi-mediated silencing of the IRAK family member Tube (but not Pelle) suppresses activation of stress kinase signaling induced by ER stress in Drosophila cells. The action of IRAK2 maps to the IRE1 pathway, rather than the PERK or ATF6 components of the UPR. Interestingly, ER stress also induces IRAK2 gene expression in an IRE1/XBP1-dependent manner, suggesting a mutually supporting amplification loop involving IRAK2 and IRE1. In vivo, ER stress induces Irak2 expression in mice. Moreover, Irak2 gene knockout mice display defects in ER stress-induced CHOP expression and IRE1 pathway signaling. These findings demonstrate an unexpected linkage of the innate immunity machinery to UPR signaling, revealing IRAK2 as a novel amplifier of the IRE1 pathway.
- Published
- 2013