title: Ubiquitin-like protein MNSFβ regulates TLR-2-mediated signal transduction.
abstract: Post-translational modification by monoclonal nonspecific suppressor factor β (MNSFβ) has been involved in the regulation of a variety of cellular processes. Previous studies have demonstrated that MNSFβ covalently binds to the intracellular pro-apoptotic protein Bcl-G and regulates TLR-4-mediated signal transduction. Recently, we found that MNSFβ also covalently conjugates to endophilin II, a member of the endophilin A family, and inhibits the signal pathway upstream of IKK activation, but not downstream of TLR-2 signaling. In this study, we further examined the mechanism of action of MNSFβ in TLR-2-mediated signal transduction in macrophage-like cell line Raw264.7 cells. Although MNSFβ siRNA enhanced Pam(3)CDK(4) (TLR-2-specific ligand)-stimulated TNFα production, Bcl-G siRNA did not affect. MNSFβ cDNA inhibited the Pam(3)CDK(4)-stimulated TNFα production. High-molecular weight (130 kDa) MNSFβ-adduct was induced in Pam(3)CDK(4)-stimulated Raw264.7 cells. This MNSFβ-adduct was not induced by LPS, indicative of the specificity of TLR-2-mediated signal transduction. Similar observations were seen in BALB/c peritoneal macrophages. Interestingly, 40-kDa MNSFβ-adduct was tyrosine phosphorylated by Pam(3)CDK(4) stimulation. Collectively, novel MNSFβ-adducts may regulate TLR-2 signaling pathway in macrophages.
authors.affiliation: Department of Cooperative Medical Research, Collaboration Center, Shimane University, Izumo 693-8501, Japan. nkmr0515@med.shimane-u.ac.jp
authors.forename: Morihiko
authors.initials: M
authors.lastname: Nakamura
authors.forename: Jun
authors.initials: J
authors.lastname: Watanabe
authors.forename: Natsuko
authors.initials: N
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics*; D051550:I-kappa B Kinase / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D011485:Protein Binding; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034741:RNA, Small Interfering; D015398:Signal Transduction / Q000235:genetics; D013491:Suppressor Factors, Immunologic / Q000235:genetics / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D013491:Suppressor Factors, Immunologic; C493486:Tlr2 protein, mouse; D051195:Toll-Like Receptor 2; D014409:Tumor Necrosis Factor-alpha; C528010:endophilin II, mouse; C072169:monoclonal nonspecific suppressor factor; D051550:I-kappa B Kinase