Prostaglandin E Synthase 3, Cytosolic (PTGES3)

P23 was first observed as a component of the unactivated avian progesterone receptor complex, along with HSP70 and HSP90 (Smith et al., 1990). Using the chicken p23 sequence as probe, Johnson et al. (1994) cloned P23 from a human testis cDNA library. The deduced 160-amino acid protein has a calculated molecular mass of about 19 kD and contains several putative phosphorylation sites. P23 shares about 96% sequence identity with the chicken homolog. Western blot analysis revealed a 23-kD band in tissue and cell lysates from several mammalian species including human.Freeman and Yamamoto (2002) determined that the P23 molecular chaperone localizes to genomic response elements in a hormone-dependent manner and showed that it could disrupt receptor-mediated transcriptional activation.