title: SUMOylation attenuates c-Maf-dependent IL-4 expression.
abstract: The function of transcription factors can be critically regulated by SUMOylation. c-Maf, the cellular counterpart of v-maf oncogene, is a potent transactivator of the IL-4 gene in Th2 cells. We found in a yeast two-hybrid screen that c-Maf can interact with Ubc9 and PIAS1, two key enzymes of the SUMOylation pathway. In this study, we report that c-Maf co-localized with these two SUMO (small ubiquitin-like modifier) ligases in the nucleus and that c-Maf can be SUMOylated in vitro and also in primary Th2 cells. We also demonstrated that lysine-33 is the dominant, if not the only, SUMO acceptor site of c-Maf. SUMOylation of c-Maf attenuated its transcriptional activity. Reciprocally, a SUMOylation resistant c-Maf was more potent than WT-c-Maf in driving IL-4 production in c-Maf-deficient Th2 cells. Furthermore, we showed that ablation of the SUMO site did not alter the subcellular localization or the stability of c-Maf protein but instead enhanced its recruitment to the Il4-promoter. We conclude that SUMOylation at lysine-33 is a functionally critical post-translational modification event of c-Maf in Th cells.
authors.affiliation: Graduate Institute of Immunology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Bo-Shiou
authors.initials: BS
authors.lastname: Lin
authors.forename: Pei-Yun
authors.initials: PY
authors.lastname: Tsai
authors.forename: Wan-Yun
authors.initials: WY
authors.lastname: Hsieh
authors.forename: Hsiao-Wei
authors.initials: HW
authors.lastname: Tsao
authors.forename: Meng-Wei
authors.initials: MW
authors.lastname: Liu
authors.forename: Roland
authors.initials: R
authors.lastname: Grenningloh
authors.forename: Li-Fang
authors.initials: LF
authors.lastname: Wang
authors.forename: I-Cheng
authors.initials: IC
authors.lastname: Ho
authors.forename: Shi-Chuen
authors.initials: SC
authors.lastname: Miaw
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured / Q000378:metabolism; D006801:Humans; D015847:Interleukin-4 / Q000096:biosynthesis* / Q000235:genetics; D007668:Kidney; D008239:Lysine / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D050828:Protein Inhibitors of Activated STAT / Q000737:chemistry / Q000302:isolation & purification / Q000502:physiology*; D025941:Protein Interaction Mapping; D011499:Protein Processing, Post-Translational; D051257:Proto-Oncogene Proteins c-maf / Q000737:chemistry / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D025841:Small Ubiquitin-Related Modifier Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D018418:Th2 Cells / Q000378:metabolism*; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry / Q000502:physiology*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: C508598:IL4 protein, human; C495607:MAF protein, human; C495608:Maf protein, mouse; C106529:PIAS1 protein, human; C494211:Pias1 protein, mouse; D050828:Protein Inhibitors of Activated STAT; D051257:Proto-Oncogene Proteins c-maf; D011993:Recombinant Fusion Proteins; D025841:Small Ubiquitin-Related Modifier Proteins; D015847:Interleukin-4; D044763:Ubiquitin-Conjugating Enzymes; D000098843:Ubiquitin-Conjugating Enzyme UBC9; D008239:Lysine