title: Convergence of 3',5'-cyclic adenosine 5'-monophosphate/protein kinase A and glycogen synthase kinase-3beta/beta-catenin signaling in corpus luteum progesterone synthesis.
abstract: Progesterone secretion by the steroidogenic cells of the corpus luteum (CL) is essential for reproduction. Progesterone synthesis is under the control of LH, but the exact mechanism of this regulation is unknown. It is established that LH stimulates the LH receptor/choriogonadotropin receptor, a G-protein coupled receptor, to increase cAMP and activate cAMP-dependent protein kinase A (PKA). In the present study, we tested the hypothesis that cAMP/PKA-dependent regulation of the Wnt pathway components glycogen synthase kinase (GSK)-3beta and beta-catenin contributes to LH-dependent steroidogenesis in luteal cells. We observed that LH via a cAMP/PKA-dependent mechanism stimulated the phosphorylation of GSK3beta at N-terminal Ser9 causing its inactivation and resulted in the accumulation of beta-catenin. Overexpression of N-terminal truncated beta-catenin (Delta90 beta-catenin), which lacks the phosphorylation sites responsible for its destruction, significantly augmented LH-stimulated progesterone secretion. In contrast, overexpression of a constitutively active mutant of GSK3beta (GSK-S9A) reduced beta-catenin levels and inhibited LH-stimulated steroidogenesis. Chromatin immunoprecipitation assays demonstrated the association of beta-catenin with the proximal promoter of the StAR gene, a gene that expresses the steroidogenic acute regulatory protein, which is a cholesterol transport protein that controls a rate-limiting step in steroidogenesis. Collectively these data suggest that cAMP/PKA regulation of GSK3beta/beta-catenin signaling may contribute to the acute increase in progesterone production in response to LH.
authors.affiliation: Department of Obstetrics and Gynecology, Olson Center for Women's Health, 3255 Nebraska Medical Center, Omaha, Nebraska 68198, USA.
authors.forename: Lynn
authors.initials: L
authors.lastname: Roy
authors.forename: Claudia A
authors.initials: CA
authors.lastname: McDonald
authors.forename: Chao
authors.initials: C
authors.lastname: Jiang
authors.forename: Dulce
authors.initials: D
authors.lastname: Maroni
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Zeleznik
authors.forename: Todd A
authors.initials: TA
authors.lastname: Wyatt
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Hou
authors.forename: John S
authors.initials: JS
authors.lastname: Davis
mesh_terms: D000818:Animals; D002417:Cattle; D003338:Corpus Luteum / Q000201:enzymology / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D005260:Female; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D007986:Luteinizing Hormone / Q000378:metabolism; D010766:Phosphorylation; D011374:Progesterone / Q000096:biosynthesis*; D015398:Signal Transduction; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
chemical_list: D051176:beta Catenin; D011374:Progesterone; D007986:Luteinizing Hormone; D000242:Cyclic AMP; D000071679:Glycogen Synthase Kinase 3 beta; D017868:Cyclic AMP-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3