title: Ubiquitination of RORγt at Lysine 446 Limits Th17 Differentiation by Controlling Coactivator Recruitment.
abstract: The transcription factor retinoid acid-related orphan receptor γ t (RORγt) directs the differentiation of Th17 cells. Th17 cells mediate pathological immune responses responsible for autoimmune diseases, including psoriasis and multiple sclerosis. Previous studies focused on RORγt target genes and their function in Th17 differentiation. In this study, we assessed posttranscriptional regulation of RORγt and identified a functional ubiquitination site, K446. Mutation of K446 to arginine to prevent ubiquitination greatly enhanced recruitment of steroid receptor coactivator 1 (SRC1), a coactivator critical for RORγt activity. Correspondingly, the K446 to arginine mutation potentiated Th17 differentiation. We also showed that ubiquitin-specific protease (USP)15 interacted with RORγt, removed ubiquitin from K446, and stimulated RORγt activity by enhancing coactivator SRC1 recruitment. Knockdown of USP15 or expression of inactive USP15 impaired Th17 differentiation, suggesting a positive role for USP15-mediated deubiquitination of RORγt in Th17 differentiation. Therefore, ubiquitination of K446 limits RORγt-mediated Th17 differentiation by inhibiting the recruitment of coactivator SRC1. Our study will inform the development of treatments that target RORγt ubiquitination pathways to limit Th17-mediated autoimmunity.
authors.affiliation: Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010;
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: He
authors.affiliation: Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010;
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010;
authors.forename: Jian
authors.identifier: 0000-0003-3112-0534
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010;
authors.forename: Subha
authors.initials: S
authors.lastname: Sen
authors.affiliation: Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010; Irell & Manella Graduate School of Biological Sciences, City of Hope, Duarte, CA 91010;
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095; and.
authors.forename: Yousang
authors.identifier: 0000-0002-2821-9245
authors.initials: Y
authors.lastname: Gwack
authors.affiliation: Research Center for Liver Disease, Keck School of Medicine of University of Southern California, Los Angeles, CA 90089.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, CA 91010; zsun@coh.org.
authors.forename: Zuoming
authors.identifier: 0000-0003-1896-6666
authors.initials: Z
authors.lastname: Sun
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D005434:Flow Cytometry; D047468:Immunoprecipitation; D008239:Lysine / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D056920:Nuclear Receptor Coactivator 1 / Q000378:metabolism*; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D058504:Th17 Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D054875:Ubiquitination
chemical_list: D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; C539901:Rorc protein, mouse; C538861:Ncoa1 protein, mouse; D056920:Nuclear Receptor Coactivator 1; D008239:Lysine