title: Signaling Pathway for Endothelin-1- and Phenylephrine-Induced cAMP Response Element Binding Protein Activation in Rat Ventricular Myocytes: Role of Inositol 1,4,5-Trisphosphate Receptors and CaMKII.
abstract: OBJECTIVE
  Endothelin-1 (ET-1) and the α<Sub>1</Sub>-adrenoceptor agonist phenylephrine (PE) activate cAMP response element binding protein (CREB), a transcription factor implicated in cardiac hypertrophy. The signaling pathway involved in CREB activation by these hypertrophic stimuli is poorly understood. We examined signaling pathways for ET-1- or PE-induced cardiac CREB activation.
  
  
  METHODS
  Western blotting was performed with pharmacological and genetic interventions in rat ventricular myocytes.
  
  
  RESULTS
  ET-1 and PE increased CREB phosphorylation, which was inhibited by blockade of phospholipase C, the extracellular-signal-regulated kinase 1/2 (ERK1/2) pathway, protein kinase C (PKC) or Ca2+-calmodulin-dependent protein kinase II (CaMKII). Intracellular Ca2+ buffering decreased ET-1- and PE-induced CREB phosphorylation by ≥80%. Sarcoplasmic reticulum Ca2+ pump inhibitor, inositol 1,4,5-trisphosphate receptor (IP<Sub>3</Sub>R) blockers, or type 2 IP<Sub>3</Sub>R (IP<Sub>3</Sub>R2) knock-out abolished ET-1- or PE-induced CREB phosphorylation. ET-1 and PE increased phosphorylation of CaMKII and ERK1/2, which was eliminated by IP<Sub>3</Sub>R blockade/knock-out or PKC inhibition. Activation of CaMKII, but not ERK1/2, by these agonists was sensitive to Ca2+ buffering or to Gö6976, the inhibitor of Ca2+-dependent PKC and protein kinase D (PKD).
  
  
  CONCLUSIONS
  CREB phosphorylation by ET-1 and PE may be mainly mediated by IP<Sub>3</Sub>R2/Ca2+-PKC-PKD-CaMKII signaling with a minor contribution by ERK1/2, linked to IP<Sub>3</Sub>R2 and Ca2+-independent PKC, in ventricular myocytes.
authors.forename: Krishna P
authors.initials: KP
authors.lastname: Subedi
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Son
authors.forename: Bojjibabu
authors.initials: B
authors.lastname: Chidipi
authors.forename: Seong-Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Kyeong-Hee
authors.initials: KH
authors.lastname: Kim
authors.forename: Sun-Hee
authors.initials: SH
authors.lastname: Woo
authors.forename: Joon-Chul
authors.initials: JC
authors.lastname: Kim
mesh_terms: D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D002227:Carbazoles / Q000494:pharmacology; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D019332:Endothelin-1 / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D002227:Carbazoles; D017362:Cyclic AMP Response Element-Binding Protein; D019332:Endothelin-1; D005419:Flavonoids; D053496:Inositol 1,4,5-Trisphosphate Receptors; C580990:Ip3r2 protein, mouse; C081021:Go 6976; D010656:Phenylephrine; C089212:protein kinase D; D011493:Protein Kinase C; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D010738:Type C Phospholipases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one
keywords: Ca2+-calmodulin-dependent protein kinase II; Inositol 1,4,5-trisphosphate receptor; Protein kinase C; Ventricular myocytes; cAMP response element binding protein