Progesterone receptor membrane component 1 (abbreviated PGRMC1) is a protein which co-purifies with progesterone binding proteins in the liver and ovary.[1][2] In humans, the PGRMC1 protein is encoded by the PGRMC1gene.[3] The Sigma-2 receptor was recently identified as a protein that binds the PGRMC1 protein.[4]
The sole biochemical function of PGRMC1 is heme-binding.[5][6] PGRMC1 shares key structural motifs with cytochrome b5.[7] PGRMC1 binds and activates P450 proteins,[8][9][10] which are important in drug, hormone and lipid metabolism. PGRMC1 also binds to PAIR-BP1 (plasminogen activator inhibitor RNA-binding protein-1).[2] However, its expression outside of the reproductive tract and in males suggests multiple functions for the protein. These may include binding to Insig (insulin-induced gene),[11] which regulates cholesterol synthesis.[12]
PGRMC1 is highly expressed in the liver and kidney in humans[3] with lower expression in the brain, lung, heart, skeletal muscle and pancreas.[3][13][14] In rodents, PGRMC1 is found in the liver, lung, kidney and brain.[13][14] PGRMC1 is over-expressed in breast tumors and in cancer cell lines from the colon, thyroid, ovary, lung, and cervix.[15][16]Microarray analyses have detected PGRMC1 expression in colon, lung and breast tumors.[17][18][19]
PGRMC1 expression is induced by the non-genotoxic carcinogen2,3,7,8-tetrachlorodibenzo-p-dioxin in the rat liver,[14] but this induction is specific to males.[20] PGRMC1 is expressed in the ovary and corpus luteum, where its expression is induced by progesterone[21] and during pregnancy,[22] respectively. PGRMC1/25-Dx is expressed in various regions of the brain [hypothalamic area, circumventricular organs, ependymal cells of the lateral ventricles, meninges,[13][23] including regions known to facilitate lordosis.[13]
Binding to heme and cytochrome P450s
The PGRMC1 yeast homologue, Dap1 (damage associated protein 1), binds heme[6][24] through a penta-coordinate mechanism.[6][25] Yeast cells lacking the DAP1 gene are sensitive to DNA damage,[26] and heme-binding is essential for damage resistance.[24] Dap1 is also required for a critical step in cholesterol synthesis in which the P450 protein Erg11/Cyp51 removes a methyl group from lanosterol.[8][24][26][27] Erg11/Cyp51 is the target of the azole antifungal drugs. As a result, yeast cells lacking the DAP1 gene are highly sensitive to antifungal drugs[8][24][26] This function is conserved between the unrelated fungi S. cerevisiae and S. pombe. Dap1 also regulates the metabolism of iron in yeast.[27]
In yeast and humans, PGRMC1 binds directly to P450 proteins, including CYP51A1, CYP3A4, CYP7A1 and CYP21A2.[8] PGRMC1 also activates Cyp21 when the two proteins are co-expressed,[9][10] indicating that PGRMC1 promotes progesterone turnover. Just as Dap1 is required for the action of Erg11 in the synthesis of ergosterol in yeast, PGRMC1 regulates the Cyp51-catalyzed demethylation step in human cholesterol synthesis.[8] Thus, PGRMC1 and its homologues bind and regulate P450 proteins, and it has been likened to “a helping hand for P450 proteins”.[28]
Roles in signaling and apoptosis
The yeast PGRMC1 homologue is required for resistance to damage.[26] PGRMC1 also promotes survival in human cancer cells after treatment with chemotherapy.[2][5] In contrast, PGRMC1 promotes cell death in cancer cells after oxidative damage.[29] PGRMC1 alters several known survival signaling proteins, including the Aktprotein kinase and the cell death-associated protein IκB.[29] Progesterone inhibits apoptosis in immortalized granulosa cells, and this activity requires PGRMC1 and its binding partner, PAIR-BP1 (plasminogen activator inhibitor RNA-binding protein-1).[2] However, PAIR-BP1 is not a progesterone binding protein, and the component of the PGRMC1 complex that binds to progesterone is unknown.
↑ 3.03.13.2Gerdes D, Wehling M, Leube B, Falkenstein E (Jul 1998). "Cloning and tissue expression of two putative steroid membrane receptors". Biological Chemistry. 379 (7): 907–11. doi:10.1515/bchm.1998.379.7.907. PMID9705155.
↑Xu J, Zeng C, Chu W, Pan F, Rothfuss JM, Zhang F, Tu Z, Zhou D, Zeng D, Vangveravong S, Johnston F, Spitzer D, Chang KC, Hotchkiss RS, Hawkins WG, Wheeler KT, Mach RH (2011). "Identification of the PGRMC1 protein complex as the putative sigma-2 receptor binding site". Nature Communications. 2 (2): 380. doi:10.1038/ncomms1386. PMID21730960.
↑ 5.05.1Crudden G, Chitti RE, Craven RJ (Jan 2006). "Hpr6 (heme-1 domain protein) regulates the susceptibility of cancer cells to chemotherapeutic drugs". The Journal of Pharmacology and Experimental Therapeutics. 316 (1): 448–55. doi:10.1124/jpet.105.094631. PMID16234411.
↑ 9.09.1Min L, Strushkevich NV, Harnastai IN, Iwamoto H, Gilep AA, Takemori H, Usanov SA, Nonaka Y, Hori H, Vinson GP, Okamoto M (Nov 2005). "Molecular identification of adrenal inner zone antigen as a heme-binding protein". The FEBS Journal. 272 (22): 5832–43. doi:10.1111/j.1742-4658.2005.04977.x. PMID16279947.
↑ 10.010.1Min L, Takemori H, Nonaka Y, Katoh Y, Doi J, Horike N, Osamu H, Raza FS, Vinson GP, Okamoto M (Feb 2004). "Characterization of the adrenal-specific antigen IZA (inner zone antigen) and its role in the steroidogenesis". Molecular and Cellular Endocrinology. 215 (1–2): 143–8. doi:10.1016/j.mce.2003.11.025. PMID15026187.
↑Suchanek M, Radzikowska A, Thiele C (Apr 2005). "Photo-leucine and photo-methionine allow identification of protein-protein interactions in living cells". Nature Methods. 2 (4): 261–7. doi:10.1038/nmeth752. PMID15782218.
↑ 14.014.114.2Selmin O, Lucier GW, Clark GC, Tritscher AM, Vanden Heuvel JP, Gastel JA, Walker NJ, Sutter TR, Bell DA (Dec 1996). "Isolation and characterization of a novel gene induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in rat liver". Carcinogenesis. 17 (12): 2609–15. doi:10.1093/carcin/17.12.2609. PMID9006096.
↑Crudden G, Loesel R, Craven RJ (2005). "Overexpression of the cytochrome p450 activator hpr6 (heme-1 domain protein/human progesterone receptor) in tumors". Tumour Biology. 26 (3): 142–6. doi:10.1159/000086485. PMID15970648.
↑Peluso JJ, Liu X, Saunders MM, Claffey KP, Phoenix K (May 2008). "Regulation of ovarian cancer cell viability and sensitivity to cisplatin by progesterone receptor membrane component-1". The Journal of Clinical Endocrinology and Metabolism. 93 (5): 1592–9. doi:10.1210/jc.2007-2771. PMID18319313.
↑Difilippantonio S, Chen Y, Pietas A, Schlüns K, Pacyna-Gengelbach M, Deutschmann N, Padilla-Nash HM, Ried T, Petersen I (Sep 2003). "Gene expression profiles in human non-small and small-cell lung cancers". European Journal of Cancer. 39 (13): 1936–47. doi:10.1016/S0959-8049(03)00419-2. PMID12932674.
↑Dressman HK, Hans C, Bild A, Olson JA, Rosen E, Marcom PK, Liotcheva VB, Jones EL, Vujaskovic Z, Marks J, Dewhirst MW, West M, Nevins JR, Blackwell K (Feb 2006). "Gene expression profiles of multiple breast cancer phenotypes and response to neoadjuvant chemotherapy". Clinical Cancer Research. 12 (3 Pt 1): 819–26. doi:10.1158/1078-0432.CCR-05-1447. PMID16467094.
↑Irby RB, Malek RL, Bloom G, Tsai J, Letwin N, Frank BC, Verratti K, Yeatman TJ, Lee NH (Mar 2005). "Iterative microarray and RNA interference-based interrogation of the SRC-induced invasive phenotype". Cancer Research. 65 (5): 1814–21. doi:10.1158/0008-5472.CAN-04-3609. PMID15753379.
↑Selmin O, Thorne PA, Blachere FM, Johnson PD, Romagnolo DF (Feb 2005). "Transcriptional activation of the membrane-bound progesterone receptor (mPR) by dioxin, in endocrine-responsive tissues". Molecular Reproduction and Development. 70 (2): 166–74. doi:10.1002/mrd.20090. PMID15570619.
↑Nilsson EE, Stanfield J, Skinner MK (Dec 2006). "Interactions between progesterone and tumor necrosis factor-alpha in the regulation of primordial follicle assembly". Reproduction. 132 (6): 877–86. doi:10.1530/REP-06-0045. PMID17127748.
↑Cai Z, Stocco C (Dec 2005). "Expression and regulation of progestin membrane receptors in the rat corpus luteum". Endocrinology. 146 (12): 5522–32. doi:10.1210/en.2005-0759. PMID16123161.
↑Meffre D, Delespierre B, Gouézou M, Leclerc P, Vinson GP, Schumacher M, Stein DG, Guennoun R (Jun 2005). "The membrane-associated progesterone-binding protein 25-Dx is expressed in brain regions involved in water homeostasis and is up-regulated after traumatic brain injury". Journal of Neurochemistry. 93 (5): 1314–26. doi:10.1111/j.1471-4159.2005.03127.x. PMID15934950.
↑ 27.027.1Craven RJ, Mallory JC, Hand RA (Dec 2007). "Regulation of iron homeostasis mediated by the heme-binding protein Dap1 (damage resistance protein 1) via the P450 protein Erg11/Cyp51". The Journal of Biological Chemistry. 282 (50): 36543–51. doi:10.1074/jbc.M706770200. PMID17954932.
↑ 29.029.1Hand RA, Craven RJ (Oct 2003). "Hpr6.6 protein mediates cell death from oxidative damage in MCF-7 human breast cancer cells". Journal of Cellular Biochemistry. 90 (3): 534–47. doi:10.1002/jcb.10648. PMID14523988.