Functions as an E3-type small ubiquitin-like modifier (SUMO) ligase, stabilizing the interaction between UBE2I and the substrate, and as a SUMO-tethering factor. Plays a crucial role as a transcriptional coregulation in various cellular pathways, including the STAT pathway, the p53 pathway and the steroid hormone signaling pathway. In vitro, binds A/T-rich DNA. The effects of this transcriptional coregulation, transactivation or silencing, may vary depending upon the biological context. Together with PRMT1, may repress STAT1 transcriptional activity, in the late phase of interferon gamma (IFN-gamma) signaling. Interacts with NCOA2 and AR. Interacts with NR2C1; the interaction promotes its sumoylation. Interacts with DDX21, CSRP2, AXIN1, JUN, UBE2I, SUMO1, SATB2, PLAG1, TP53 and STAT1 (dimer), following IFNA1-stimulation. Interacts with SP3 (preferentially when SUMO-modified). Interacts with KLF8; the interaction results in SUMO ligation and repression of KLF8 transcriptional activity and of its cell cycle progression into G(1) phase. Interacts with STAT1. Interacts with CHUK/IKKA; this interaction induces PIAS1 phosphorylation. Interacts with PTK2/FAK1; the interaction promotes its sumoylation. Interacts with DDX5. Expressed in numerous tissues with highest level in testis. Belongs to the PIAS family. Note: This description may include information from UniProtKB.
Molecular Function: protein domain specific binding; protein binding; enzyme binding; DNA binding; androgen receptor binding; zinc ion binding; ubiquitin protein ligase binding; transcription coactivator activity; SUMO ligase activity; transcription corepressor activity
Biological Process: positive regulation of protein sumoylation; protein sumoylation; transcription, DNA-dependent; positive regulation of smooth muscle cell differentiation; positive regulation of proteasomal ubiquitin-dependent protein catabolic process; positive regulation of transcription, DNA-dependent; cytokine and chemokine mediated signaling pathway; androgen receptor signaling pathway; spermatogenesis; negative regulation of transcription from RNA polymerase II promoter; JAK-STAT cascade; protein-DNA complex assembly; regulation of cell proliferation
Alt. Names/Synonyms: AR interacting protein; DDXBP1; DEAD/H (Asp-Glu-Ala-Asp/His) box binding protein 1; DEAD/H box-binding protein 1; E3 SUMO-protein ligase PIAS1; GBP; Gu-binding protein; GU/RH-II; MGC141878; MGC141879; PIAS1; Protein inhibitor of activated STAT protein 1; protein inhibitor of activated STAT, 1; protein inhibitor of activated STAT-1; RNA helicase II-binding protein; zinc finger, MIZ-type containing 3; ZMIZ3
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.