title: Human chorionic gonadotropin (hCG) induces MAPK3/1 phosphorylation in the zebrafish ovarian follicle cells independent of EGF/EGFR pathway.
abstract: In mammals, human chorionic gonadotropin (hCG), a luteinizing hormone (LH) analogue, induces MAPK3/1 phosphorylation in the granulosa cells and this event is largely dependent on epidermal growth factor receptor (EGFR) activity. However, whether this mechanism also works in other vertebrates such as fish remains unknown. Here, we showed that treatment of cultured zebrafish ovarian follicle cells with hCG also resulted in MAPK3/1 phosphorylation without affecting the total protein level of MAPK3/1. The phosphorylation level peaked at 5 min and then declined to the basal level after 40 min of hCG treatment. Further experiment showed that H89 (a PKA inhibitor) could abolish hCG-stimulated MAPK3/1 phosphorylation, but had no effect on EGF-induced phosphorylation, suggesting a mediating role for cAMP/PKA in hCG activation of MAPK3/1. On the other hand, AG1478 (an EGFR inhibitor) completely blocked EGF-stimulated MAPK3/1 phosphorylation, but had no effect on the hCG-induced MAPK3/1 phosphorylation. These data indicate that similar to its action in mammals, hCG/LH also stimulated MAPK3/1 phosphorylation in the zebrafish ovarian follicle cells; however, unlike the situation in the mammalian ovary, the hCG-stimulated MAPK3/1 phosphorylation in cultured zebrafish ovarian follicle cells was independent of EGFR.
authors: School of Life Sciences and Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors: Chi-Kin
authors: CK
authors: Chung
authors: Wei
authors: W
authors: Ge
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D015027:Zebrafish / Q000378:metabolism*
chemical_list: D006063:Chorionic Gonadotropin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3