Journal Article

Characterization of cAMP/PKA/CREB signaling cascade in the bonnet monkey corpus luteum: expressions of inhibin-α and StAR during different functional status

S. Priyanka and R. Medhamurthy

in MHR: Basic science of reproductive medicine

Published on behalf of European Society of Human Reproduction and Embryology

Volume 13, issue 6, pages 381-390
Published in print June 2007 | ISSN: 1360-9947
Published online April 2007 | e-ISSN: 1460-2407 | DOI: http://dx.doi.org/10.1093/molehr/gam015
Characterization of cAMP/PKA/CREB signaling cascade in the bonnet monkey corpus luteum: expressions of inhibin-α and StAR during different functional status

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Luteinizing hormone mediates its nuclear action primarily by activating cAMP/Protein kinase A (PKA) pathway leading to phosphorylation of cAMP response element binding (CREB) family of transcription factors. Earlier studies have documented altered cAMP responsiveness of luteal cells during maturation, and in the rhesus monkey, extinction of CREB expression following luteinization and ovulation. In the course of studies aimed at characterizing LH-cAMP signaling pathway, we serendipitously discovered that CREB is after all present in the monkey corpus luteum (CL). The present experiments were carried out to examine the PKA activity, CREB expression and RT–PCR expression of inhibin-α (Inh-α) subunit and steroidogenic acute regulatory protein (StAR) in CL obtained from a variety of model systems. PKA activity in the CL was maintained throughout the luteal phase. Messenger RNA expression by RT–PCR and Northern analyses and protein levels employing antibodies specific to total- and phospho-forms demonstrated presence of CREB in the CL. Additionally, immuno-histo/cytochemical analyses, Electrophoretic mobility shift assays and chromatin immunoprecipitation assays for Inh-α and StAR genes further confirmed the presence of CREB in the CL. The present study, contrary to an earlier report, demonstrates the presence of CREB (both transcript and protein) in the monkey CL. Also, analysis of expression of Inh-α and StAR genes (considered to be cAMP responsive), during different functional status of CL suggests that LH regulates their expression perhaps by cAMP/PKA/CREB pathway.

Keywords: bonnet monkey; corpus luteum; CREB; inhibin-α and StAR expressions; PKA

Journal Article.  8283 words.  Illustrated.

Subjects: Reproductive Medicine

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