A complex of Ca(V)1.2/PKC is involved in muscarinic signaling in smooth muscle

作者：Huster Maria; Frei Eva; Hofmann Franz; Wegener Joerg W^*

来源：The FASEB Journal, 2010, 24(8): 2651-2659.

DOI：10.1096/fj.09-149856

• micturition
• contraction
• urinary bladder
• phospholipase D

Here we present functional and biochemical evidence for a Ca2+ channel (Ca(V)1.2)/protein kinase C (PKC) signaling complex being a key player in muscarinic regulation of urinary bladder smooth muscle. Muscarinic stimulation induced Ca2+ signals and concomitant contractions in detrusor muscle from mice that were dependent on functional Ca2+ channels. These signals were still present in muscles being depolarized by 85 mM extracellular K+. Muscarinic-induced contractions were reduced by a PKC inhibitor [bisindolylmaleimide I (BIM-I)] and a phospholipase D (PLD) inhibitor (1-butanol). A phorbol ester (PDBu) enlarged muscarinic-induced Ca2+ signals and contractions. The effects of BIM-I and PDBu were inhibited by isradipine and/or absent in muscles from Ca(V)1.2-deficient mice. Both carbachol and PDBu increased Ca(V)1.2 channel currents in isolated bladder myocytes. Blue native-PAGE electrophoresis revealed that Ca(V)1.2, PKC, and PLD are closely associated in muscles being previously stimulated by carbachol. Immunoprecipitation using anti-Ca(V)1.2 followed by Western blotting demonstrated that Ca(V)1.2 and PKC are coupled in stimulated muscles from wild-type mice. Autoradiography on immunoprecipitates showed that Ca(V)1.2 is a substrate for PKC-mediated phosphorylation. These findings suggest that a signaling complex consisting of Ca(V)1.2, PKC, and, probably, PLD controls muscarinic-mediated phasic contraction of urinary bladder smooth muscle.-Huster, M., Frei, E., Hofmann, F., Wegener, J.W. A complex of Ca(V)1.2/PKC is involved in muscarinic signaling in smooth muscle. FASEB J. 24, 2651-2659 (2010). www.fasebj.org

• 出版日期2010-8