Prostaglandin E synthase 3 (cytosolic) is an enzyme that in humans is encoded by the PTGES3 gene. The protein encoded by this gene is also known as p23 which functions as a chaperone which is required for proper functioning of the glucocorticoid and other steroid receptors. 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.