Identification of optineurin as an interleukin-1 receptor-associated kinase 1-binding protein and its role in regulation of MyD88-dependent signaling

• Published in: The Journal of biological chemistry Vol. 292; no. 42; pp. 17250 - 17257
• Main Authors: Tanishima, Mitsuyoshi, Takashima, Shigeo, Honda, Arata, Yasuda, Daisuke, Tanikawa, Takashi, Ishii, Satoshi, MaruYama, Takashi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 20.10.2017; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Substitution; Animals; Cell Cycle Proteins; Cysteine Endopeptidases - genetics; Cysteine Endopeptidases - metabolism; Deubiquitinating Enzyme CYLD; Eye Proteins - genetics; Eye Proteins - metabolism; HEK293 Cells; Humans; interleukin 1 (IL-1); Interleukin-1 Receptor-Associated Kinases - genetics; Interleukin-1 Receptor-Associated Kinases - metabolism; Intracellular Signaling Peptides and Proteins; IRAK1; Lipopolysaccharides - pharmacology; Membrane Transport Proteins; Mice; Mutation, Missense; Myeloid Differentiation Factor 88 - genetics; Myeloid Differentiation Factor 88 - metabolism; myeloid differentiation primary response gene (MYD88); NF-kappa B - genetics; NF-kappa B - metabolism; NF-kappaB (NF-κB); RAW 264.7 Cells; Signal Transduction; Signal Transduction - drug effects; Signal Transduction - physiology; TNF Receptor-Associated Factor 6 - genetics; TNF Receptor-Associated Factor 6 - metabolism; TRAF6; Transcription Factor TFIIIA - genetics; Transcription Factor TFIIIA - metabolism; Tumor Suppressor Proteins - genetics; Tumor Suppressor Proteins - metabolism; Ubiquitination - drug effects; Ubiquitination - physiology; yeast two-hybrid; NF-kappaB (NF-κB); IRAK1; signal transduction; TRAF6; yeast two-hybrid; interleukin 1 (IL-1); myeloid differentiation primary response gene (MYD88)
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M117.813899

Upon stimulation of toll-like receptors with various microbial ligands, induction of a variety of inflammatory genes is elicited by activation of a myeloid differentiation primary-response protein 88 (MyD88)-dependent signaling pathway. Interleukin-1 (IL-1) receptor-associated kinase 1 (IRAK1) plays an essential role in this pathway by activating nuclear factor κB (NF-κB) and mitogen-activated kinases (MAPKs). Here, we identified optineurin (OPTN) as an IRAK1-binding protein by yeast two-hybrid screening using IRAK1 as bait. A C-terminal fragment of OPTN harboring a ubiquitin-binding domain was co-immunoprecipitated with IRAK1. In reporter analyses, overexpression of OPTN inhibited IL-1β-, IRAK1-, and LPS-induced NF-κB activation. Consistently, OPTN deficiency resulted in increased NF-κB activation in response to IL-1β/LPS stimulation. To address the mechanisms underlying the inhibitory effect of OPTN on NF-κB signaling, we focused on tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), which is an adaptor protein of IRAK1 and upon polyubiquitination plays a crucial role during NF-κB activation. Overexpression of OPTN prevented TRAF6 polyubiquitination. Furthermore, OPTN H486R mutant, which is unable to recruit the deubiquitinase CYLD, failed to inhibit IRAK1-induced NF-κB activation. These results suggest that the IRAK1-binding protein OPTN negatively regulates IL-1β/LPS-induced NF-κB activation by preventing polyubiquitination of TRAF6.