title: O-GlcNAc modification of Sp3 and Sp4 transcription factors negatively regulates their transcriptional activities.
abstract: The addition of O-linked N-acetylglucosamine (O-GlcNAc) on serine or threonine modifies a myriad of proteins and regulates their function, stability and localization. O-GlcNAc modification is common among chromosome-associated proteins, such as transcription factors, suggesting its extensive involvement in gene expression regulation. In this study, we demonstrate the O-GlcNAc status of the Sp family members of transcription factors and the functional impact on their transcriptional activities. We highlight the presence of O-GlcNAc residues in Sp3 and Sp4, but not Sp2, as demonstrated by their enrichment in GlcNAc positive protein fractions and by detection of O-GlcNAc residues on Sp3 and Sp4 co-expressed in Escherichia coli together with O-GlcNAc transferase (OGT) using an O-GlcNAc-specific antibody. Deletion mutants of Sp3 and Sp4 indicate that the majority of O-GlcNAc sites reside in their N-terminal transactivation domain. Overall, using reporter gene assays and co-immunoprecipitations, we demonstrate a functional inhibitory role of O-GlcNAc modifications in Sp3 and Sp4 transcription factors. Thereby, our study strengthens the current notion that O-GlcNAc modification is an important regulator of protein interactome.
authors.affiliation: ASAN Institute for Life Science, ASAN Medical Center, Seoul, Republic of Korea.
authors.forename: Changhoon
authors.initials: C
authors.lastname: Ha
authors.affiliation: Center for Vaccine Biology and Immunology, University of Rochester Medical Center, NY 14642, USA. Electronic address: Kihong_Lim@urmc.rochester.edu.
authors.forename: Kihong
authors.initials: K
authors.lastname: Lim
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism*; D004926:Escherichia coli; D017930:Genes, Reporter; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D051704:Sp2 Transcription Factor / Q000235:genetics / Q000378:metabolism; D051705:Sp3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D051706:Sp4 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D013912:Threonine / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D011994:Recombinant Proteins; C497119:SP2 protein, human; C497121:SP3 protein, human; C497124:SP4 protein, human; D051706:Sp4 Transcription Factor; D051704:Sp2 Transcription Factor; D051705:Sp3 Transcription Factor; D013912:Threonine; D012694:Serine; D008156:Luciferases; D017351:N-Acetylglucosaminyltransferases; C449880:O-GlcNAc transferase; D000117:Acetylglucosamine
keywords: Interaction; O-GlcNAc; Sp3; Sp4; Transcription