Prostaglandin E synthase 3 (PTGES3)

Prostaglandin E synthase 3 is a cytosolic enzyme encoded by the PTGES3 gene that catalyzes the conversion of prostaglandin endoperoxide H₂ (PGH₂) into prostaglandin E₂ (PGE₂), a key mediator in inflammation and other physiological processes. Beyond its enzymatic activity, it acts as a molecular co-chaperone—commonly referred to as p23—for heat shock protein 90 (HSP90), facilitating proper folding and function of several client proteins including glucocorticoid receptors. It also participates in transcriptional regulation by localizing at genomic response elements in a hormone-dependent manner and disrupting transcriptional activation complexes. The multifunctionality links it not only to eicosanoid metabolism but also broadly impacts cellular stress responses, hormonal signaling pathways, hypoxia adaptation via interaction with EGLN1/PHD2/HIF alpha proteins, and potentially disease states ranging from inflammation to cancer.[1][5][6]

Other names

PTGES3p23TEBP (Telomerase-binding protein)Cytosolic prostaglandin E synthase

For hypothetical or investigational drugs targeting this molecule, mechanisms would include inhibition of enzymatic conversion from PGH2 to PGE2 or disruption of its co-chaperone function with HSP90—potentially modulating inflammatory responses or steroid hormone signaling.