E3 SUMO-protein ligase PIAS1 (PIAS1)

Functions as an E3-type little 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.

The effects of the transcriptional coregulation, transactivation or silencing, may change depending upon the biological context. Together with PRMT1, may repress STAT1 transcriptional activity, in the late period of interferon gamma (IFN-gamma) signaling.