Is an ortholog of several human genes including PIAS2 (protein inhibitor of activated STAT 2)\; PIAS3 (protein inhibitor of activated STAT 3)\; and PIAS4. Exhibits RNA polymerase II transcription factor binding activity and SUMO ligase activity. Is involved in several processes, including cellular response to DNA damage stimulus\; embryo development\; and regulation of response to DNA damage stimulus. Localizes to the metaphase plate and nuclear chromatin. Is expressed in motor neurons.