Rapid actions of progesterone on granulosa cells.
Ovarian granulosa cells are responsive to progesterone but do not express the nuclear progesterone receptor. In an attempt to identify a receptor for progesterone (P4) in granulosa cells (GCs), an antibody built against the ligand binding site of the P4 receptor (i.e. C-262) was used. This antibody detected a 60 kDa protein in GCs as well as spontaneously immortalized granulosa cells (SIGCs). This C-262 detectable protein localizes to the plasma membrane and binds P4. Importantly, this C-262 detectable protein appears to be involved in mediating P4's biological actions. This is based on the findings that C-262 1) blocks P4's ability to inhibit mitogen-induced mitosis and apoptosis and 2) FITC-BSA-conjugated P4 binding to granulosa cells. A C-262 detectable protein was isolated using a C-262 affinity column and sequenced. This analysis identified an unnamed protein referred to as RDA288 that was found in the rat genome (Accession number: XM216160). A nearly identical unnamed protein was found in a cDNA library of mouse lung (Accession number: AK004678). Whether RDA288 functions as a membrane receptor for P4 remains to be determined.
Department of Physiology and Obstetrics and Gynecology, University of CT Health Center, 263 Farmington Ave, Farmington, CT 06030, USA. Peluso@NSO2.UCHC.EDU
John J
JJ
Peluso
D000818:Animals; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D011374:Progesterone / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011980:Receptors, Progesterone / Q000737:chemistry / Q000378:metabolism / Q000502:physiology
D011980:Receptors, Progesterone; D011374:Progesterone