Cytosolic prostaglandin synthase that catalyzes the oxidoreduction of prostaglandin endoperoxide H2 (PGH2) to prostaglandin E2 (PGE2). Molecular chaperone that localizes to genomic response elements in a hormone-dependent manner and disrupts receptor-mediated transcriptional activation, by promoting disassembly of transcriptional regulatory complexes. Facilitates HIF alpha proteins hydroxylation via interaction with EGLN1/PHD2, leading to recruit EGLN1/PHD2 to the HSP90 pathway. prostaglandin H2 = prostaglandin E2 Lipid metabolism; prostaglandin biosynthesis. Probably forms a complex composed of chaperones HSP90 and HSP70, co-chaperones STIP1/HOP, CDC37, PPP5C, PTGES3/p23, TSC1 and client protein TSC2. Binds to the progesterone receptor. Interacts with TERT; the interaction, together with HSP90AA1, is required for correct assembly and stabilization of the telomerase holoenzyme complex. Interacts (via PXLE motif) with EGLN1/PHD2, recruiting EGLN1/PHD2 to the HSP90 pathway to facilitate HIF alpha proteins hydroxylation. Interacts with HSP90AA1, FLCN, FNIP1 and FNIP2. Belongs to the p23/wos2 family.