Specificity and regulation of extracellularly regulated kinase1/2 phosphorylation through corticotropin-releasing factor (CRF) receptors 1 and 2beta by the CRF/urocortin family of peptides.
Corticotropin-releasing factor (CRF) receptor (CRFR)-mediated activation of the ERKs 1/2-p42 and -44) has been reported for CRF, urocortin (Ucn)-I, and sauvagine. Recently two new members of the CRF/Ucn family of peptides have been identified, Ucn-II/stresscopin-related peptide and Ucn-III/stresscopin. Using Chinese hamster ovary cells stably expressing CRFR1 and CRFR2beta, we show that Ucn-I, Ucn-II and Ucn-III activate ERK1/2-p42, 44 via CRFR2beta. CRF and Ucn-I but not Ucn-II or Ucn-III activates ERK1/2-p42, 44 in Chinese hamster ovary cells stably expressing CRFR1. The selectivity of the ligands for CRFR1 and CRFR2beta is shown in a time- and dose-dependent manner. The regulatory mechanisms for ERK1/2-p42, 44 activation by both receptor types are dependent on phosphatidylinositol-3 OH kinase, MAPK kinase 1, and phospholipase C. Raf-1 kinase, tyrosine kinases, and possibly intracellular Ca(2+) provide regulatory roles for Ucn-I activation of ERK1/2-p42, 44 by CRFR1 and CRFR2beta. Studies of the regulation of ERK1/2-p42, 44 by Ucn-I were extended to cell lines that endogenously express CRFR1 (AtT-20 and CATHa cells) and CRFR2 (A7r5 and CATHa cells). Use of the G(i) and G(o) protein inhibitor pertussis toxin showed that ERK1/2-p42, 44 activation by Ucn-I via CRFR1 and CRFR2beta are both G(i) and/or G(o) protein dependent. Based on the data in this study, we present putative signaling pathways by which the CRF/Ucn family of peptides activate ERK1/2-p42, 44 by CRFRs.
Brar
Bhawanjit K
BK
The Clayton Laboratories for Peptide Biology, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Chen
Alon
A
Perrin
Marilyn H
MH
Vale
Wylie
W
D000818:Animals; D016466:CHO Cells; D002460:Cell Line; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D006224:Cricetinae; D003412:Cricetulus; D004789:Enzyme Activation; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D018019:Receptors, Corticotropin-Releasing Hormone / Q000502:physiology*; D054832:Urocortins; D000099052:CRF Receptor, Type 1
C101531:CRF receptor type 2; D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases