Dephosphorylates 26S nuclear proteasomes, thereby decreasing their proteolytic activity (, ). Recruited to the 19S regulatory particle of the 26S proteasome through its interaction with 19S component PSMD2/RPN1 . Once recruited, dephosphorylates 19S component PSMC2/RPT1 which impairs PSMC2 ATPase activity and disrupts 26S proteasome assembly . Has also been reported to stimulate the proteolytic activity of the 26S proteasome .
Subcellular locations: Nucleus
Colocalizes with nuclear proteasomes.
Broadly expressed, with highest levels in placenta, lung, testis and ovary. Up-regulated in tumor tissues.