Alternative titles; symbols
HGNC Approved Gene Symbol: PTGES3
Cytogenetic location: 12q13.3 Genomic coordinates (GRCh38) : 12:56,663,349-56,688,284 (from NCBI)
P23 was first observed as a component of the unactivated avian progesterone receptor complex, along with HSP70 (see 140550) and HSP90 (see 140571) (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.
Synthesis of prostaglandin E2 (PGE2) from arachidonic acid involves multiple enzymes, and 2 isoforms of the terminal enzyme of this biosynthetic pathway, PGE synthase (PGES), have been identified. Cytosolic PTGES (cPGES) is identical to the heat-shock protein-90 (see 140571) chaperone p23 (Tanioka et al., 2000) and is functionally coupled to constitutive prostaglandin-endoperoxide H synthase-1 (176805) (Han et al., 2002). Microsomal PTGES (mPGES; 605172) is inducible by proinflammatory cytokines such as IL1B (147720). Meadows et al. (2003) studied expression and localization of both enzyme isoforms in human fetal membranes either at term or preterm, with or without labor. Western blot analysis of the amnion and choriodecidua showed no differences in amounts of either cPGES or mPGES at term or preterm, with or without labor, in either tissue with advancing gestation. Meadows et al. (2003) concluded that expression of PGES is not the rate-limiting step in PGE2 synthesis in fetal membranes at labor.
Stumpf (2025) mapped the PTGES3 gene to chromosome 12q13.3 based on an alignment of the PTGES3 sequence (GenBank BC003005) with the genomic sequence (GRCh38).
Freeman, B. C., Yamamoto, K. R. Disassembly of transcriptional regulatory complexes by molecular chaperones. Science 296: 2232-2235, 2002. [PubMed: 12077419] [Full Text: https://doi.org/10.1126/science.1073051]
Han, R., Tsui, S., Smith, T. J. Up-regulation of prostaglandin E(2) synthesis by interleukin-1-beta in human orbital fibroblasts involves coordinate induction of prostaglandin-endoperoxide H synthase-2 and glutathione-dependent prostaglandin E(2) synthase expression. J. Biol. Chem. 277: 16355-16364, 2002. [PubMed: 11847219] [Full Text: https://doi.org/10.1074/jbc.M111246200]
Johnson, J. L., Beito, T. G., Krco, C. J., Toft, D. O. Characterization of a novel 23-kilodalton protein of unactive progesterone receptor complexes. Molec. Cell. Biol. 14: 1956-1963, 1994. [PubMed: 8114727] [Full Text: https://doi.org/10.1128/mcb.14.3.1956-1963.1994]
Meadows, J. W., Eis, A. L. W., Brockman, D. E., Myatt, L. Expression and localization of prostaglandin E synthase isoforms in human fetal membranes in term and preterm labor. J. Clin. Endocr. Metab. 88: 433-439, 2003. [PubMed: 12519887] [Full Text: https://doi.org/10.1210/jc.2002-021061]
Smith, D. F., Faber, L. E., Toft, D. O. Purification of unactivated progesterone receptor and identification of novel receptor-associated proteins. J. Biol. Chem. 265: 3996-4003, 1990. [PubMed: 2303491]
Stumpf, A. M. Personal Communication. Baltimore, Md. 10/08/2025.
Tanioka, T., Nakatani, Y., Semmyo, N., Murakami, M., Kudo, I. Molecular identification of cytosolic prostaglandin E2 synthase that is functionally coupled with cyclooxygenase-1 in immediate prostaglandin E2 biosynthesis. J. Biol. Chem. 275: 32775-32782, 2000. [PubMed: 10922363] [Full Text: https://doi.org/10.1074/jbc.M003504200]