Prostaglandin E synthase 3 (PTGES3), also known as P23 or TEBP (Telomerase binding protein p23), is a ubiquitously expressed protein that functions as a cochaperone and plays an important role in signal transduction. This protein is a molecular chaperone that localizes to genomic response elements in a hormonedependent manner and disrupts receptor-mediated transcriptional activation, by promoting disassembly of transcriptional regulatory complexes.