Ansteuerung des L-Typ Ca2+ Kanals durch G-Protein gekoppelte Rezeptoren im glatten Muskel
Zusammenfassung der Projektergebnisse
We present functional and biochemical evidence for a Ca2+ channel (CaV1.2) / 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 CaV1.2-deficient mice. Both carbachol and PDBu increased CaV1.2 channel currents in isolated bladder myocytes. Blue native-PAGE electrophoresis revealed that CaV1.2, PKC, and PLD are closely associated in muscles being previously stimulated by carbachol. Immunoprecipitation using anti-CaV1.2 followed by Western blotting demonstrated that CaV1.2 and PKC are coupled in stimulated muscles from wild-type mice. Autoradiography on immunoprecipitates showed that CaV1.2 is a substrate for PKC-mediated phosphorylation. These findings suggest that a signaling complex consisting of CaV1.2, PKC, and, probably, PLD controls muscarinic-mediated phasic contraction of urinary bladder smooth muscle.
Projektbezogene Publikationen (Auswahl)
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(2009). Calcium-dependent and Calcium-independent inhibition of contraction by cGMP/cGKl in intestinal smooth muscle. American. J. Physiol., 297, G834-G839
Frei E, Huster M, Smital P, Schloßmann J, Hofmann, F Wegener JW
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(2009). Phospholipase C mediated Ca2+ signals in murine urinary bladder smooth muscle. Europ J Pharmacol, 601, 106-109
Frei E, Hofmann, F Wegener JW
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(2010). A complex of CaV1.2/PKC is involved in muscarinic signalling in smooth muscle. FASEB J, 24, 2651
Huster M, Frei E, Hofmann F, Wegener JW
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(2010). Facilitation of murine cardiac L-type Cav1,2 channel is modulated by CaMKll dependent phosphorylation of S1512 and S1570. PNAS. 107, 10285
Blaich A, Welling A, Fischer S, Wegener JW, Kostner K, Hofmann F, Moosmang S
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(2011). Facilitation and Ca2+-dependent inactivation is modified by mutation of the Cav1.2 IQ motif. JBC. 286, 26702
Poomvanicha M, Wegener JW, Blaich A, Fischer S, Domes K, Moosmang S, Hofmann F
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(2011). Truncation of murine Cav1.2 at Asp 1904 results in heart failure after birth. JBC, 286, 33863
Domes K, Ding J, Lemke T, Blaich B, Wegener JW, Brandmayr J, Moosmang S, Hofmann F
