Progesterone inhibits apoptosis in part by PGRMC1-regulated gene expression.
Progesterone receptor membrane component-1 (PGRMC1) is present in both the cytoplasm and nucleus of spontaneously immortalized granulosa cells (SIGCs). PGRMC1 is detected as a monomer in the cytoplasm and a DTT-resistant PGRMC1 dimer in the nucleus. Transfected PGRMC1-GFP localizes mainly to the cytoplasm and does not form a DTT-resistant dimer. Moreover, forced expression of PGRMC1-GFP increases the sensitivity of the SIGCs to progesterone (P4)'s anti-apoptotic action, indicating that the PGRMC1 monomer is functional. However, when endogenous PGRMC1 is depleted by siRNA treatment and replaced with PGRMC1-GFP, P4 responsiveness is not enhanced, although overall levels of PGRMC1 are increased. P4's anti-apoptotic action is also attenuated by actinomycin D, an inhibitor of RNA synthesis, and P4 activation of PGRMC1 suppresses Bad and increases Bcl2a1d expression. Taken together, the present studies suggest a genomic component to PGRMC1's anti-apoptotic mechanism of action, which requires the presence of the PGRMC1 dimer.
Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA. peluso@nso2.uchc.edu
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Peluso
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Liu
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A
Gawkowska
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Lodde
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Wu
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002461:Cell Line, Transformed; D003609:Dactinomycin / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D011980:Receptors, Progesterone / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D008565:Membrane Proteins; C486424:Pgrmc1 protein, rat; D034741:RNA, Small Interfering; D011980:Receptors, Progesterone; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D003609:Dactinomycin; D011374:Progesterone