title: PRMT1-mediated arginine methylation of PIAS1 regulates STAT1 signaling.
abstract: To elucidate the function of the transcriptional coregulator PRMT1 (protein arginine methyltranferase 1) in interferon (IFN) signaling, we investigated the expression of STAT1 (signal transducer and activator of transcription) target genes in PRMT1-depleted cells. We show here that PRMT1 represses a subset of IFNgamma-inducible STAT1 target genes in a methyltransferase-dependent manner. These genes are also regulated by the STAT1 inhibitor PIAS1 (protein inhibitor of activated STAT1). PIAS1 is arginine methylated by PRMT1 in vitro as well as in vivo upon IFN treatment. Mutational and mass spectrometric analysis of PIAS1 identifies Arg 303 as the single methylation site. Using both methylation-deficient and methylation-mimicking mutants, we find that arginine methylation of PIAS1 is essential for the repressive function of PRMT1 in IFN-dependent transcription and for the recruitment of PIAS1 to STAT1 target gene promoters in the late phase of the IFN response. Methylation-dependent promoter recruitment of PIAS1 results in the release of STAT1 and coincides with the decline of STAT1-activated transcription. Accordingly, knockdown of PRMT1 or PIAS1 enhances the anti-proliferative effect of IFNgamma. Our findings identify PRMT1 as a novel and crucial negative regulator of STAT1 activation that controls PIAS1-mediated repression by arginine methylation.
authors.affiliation: Institute of Molecular Biology and Tumor Research (IMT), Philipps-University of Marburg, 35032 Marburg, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Weber
authors.forename: Florian
authors.initials: F
authors.lastname: Maass
authors.forename: Michael
authors.initials: M
authors.lastname: Schuemann
authors.forename: Eberhard
authors.initials: E
authors.lastname: Krause
authors.forename: Guntram
authors.initials: G
authors.lastname: Suske
authors.forename: Uta-Maria
authors.initials: UM
authors.lastname: Bauer
mesh_terms: D001120:Arginine / Q000378:metabolism*; D002460:Cell Line; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007372:Interferons / Q000378:metabolism; D008745:Methylation; D011401:Promoter Regions, Genetic; D050828:Protein Inhibitors of Activated STAT / Q000378:metabolism*; D011484:Protein-Arginine N-Methyltransferases / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D050794:STAT1 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*
chemical_list: C106529:PIAS1 protein, human; D050828:Protein Inhibitors of Activated STAT; D012097:Repressor Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; D007371:Interferon-gamma; D007372:Interferons; D001120:Arginine; C099988:PRMT1 protein, human; D011484:Protein-Arginine N-Methyltransferases