title: TRAF6-mediated degradation of DOK3 is required for production of IL-6 and TNFα in TLR9 signaling.
abstract: Our previous study showed that the downstream of kinase 3 (DOK3) is degraded during macrophage stimulation with CpG. However, the underlying mechanism and role in Toll-like receptor 9 (TLR9) signaling remains elusive. In this study, we demonstrate that CpG treatment leads to ubiquitin-mediated degradation of DOK3 via interaction with an E3 ligase TNFR-associated factor 6 (TRAF6). We also identified the 27th amino acid (lysine) of DOK3 is responsible for Ly48 polyubiquitination of DOK3. Furthermore, reintroduction of DOK3 (K27R) into DOK3-deficient macrophages abolishes DOK3 degradation induced by CpG and suppresses the production of IL-6 and TNFα. More importantly, our study uncovers a novel role of an E3 ligase TRAF6, namely, TRAF6 is also able to catalyse Lys 48 polyubiquitylation of target protein except for Lys 63 polyubiquitylation.
authors.affiliation: Central Laboratory, The Second Hospital of Jilin University, Changchun 130041, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.affiliation: Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Tang
authors.affiliation: Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, China.
authors.forename: Pan
authors.initials: P
authors.lastname: Wei
authors.affiliation: Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, China.
authors.forename: Wanchun
authors.initials: W
authors.lastname: Sun
authors.affiliation: Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, Shandong University, Qilu Hospital, Jinan, Shandong 250012, China.
authors.forename: Shuangxi
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory for Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun 130062, China. Electronic address: Qishengpeng@yahoo.com.
authors.forename: Qisheng
authors.initials: Q
authors.lastname: Peng
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D015151:Immunoblotting; D047468:Immunoprecipitation; D015850:Interleukin-6 / Q000096:biosynthesis*; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D051379:Mice; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D048029:TNF Receptor-Associated Factor 6 / Q000276:immunology / Q000378:metabolism*; D051217:Toll-Like Receptor 9 / Q000276:immunology / Q000378:metabolism*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C406768:Dok3 protein, mouse; D015850:Interleukin-6; D034741:RNA, Small Interfering; D048029:TNF Receptor-Associated Factor 6; C495370:Tlr9 protein, mouse; D051217:Toll-Like Receptor 9; D014409:Tumor Necrosis Factor-alpha; C577686:interleukin-6, mouse
keywords: DOK3; TLR9; TRAF6