title: Loss of β-adrenergic-stimulated phosphorylation of CaV1.2 channels on Ser1700 leads to heart failure.
abstract: L-type Ca2+currents conducted by voltage-gated calcium channel 1.2 (CaV1.2) initiate excitation-contraction coupling in the heart, and altered expression of CaV1.2 causes heart failure in mice. Here we show unexpectedly that reducing β-adrenergic regulation of CaV1.2 channels by mutation of a single PKA site, Ser1700, in the proximal C-terminal domain causes reduced contractile function, cardiac hypertrophy, and heart failure without changes in expression, localization, or function of the CaV1.2 protein in the mutant mice (SA mice). These deficits were aggravated with aging. Dual mutation of Ser1700 and a nearby casein-kinase II site (Thr1704) caused accelerated hypertrophy, heart failure, and death in mice with these mutations (STAA mice). Cardiac hypertrophy was increased by voluntary exercise and by persistent β-adrenergic stimulation. PKA expression was increased, and PKA sites Ser2808 in ryanodine receptor type-2, Ser16 in phospholamban, and Ser23/24 in troponin-I were hyperphosphorylated in SA mice, whereas phosphorylation of substrates for calcium/calmodulin-dependent protein kinase II was unchanged. The Ca2+pool in the sarcoplasmic reticulum was increased, the activity of calcineurin was elevated, and calcineurin inhibitors improved contractility and ameliorated cardiac hypertrophy. Cardio-specific expression of the SA mutation also caused reduced contractility and hypertrophy. These results suggest engagement of compensatory mechanisms, which initially may enhance the contractility of individual myocytes but eventually contribute to an increased sensitivity to cardiovascular stress and to heart failure in vivo. Our results demonstrate that normal regulation of CaV1.2 channels by phosphorylation of Ser1700 in cardiomyocytes is required for cardiovascular homeostasis and normal physiological regulation in vivo.
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195.
authors.forename: Linghai
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Pathology, University of Washington, Seattle, WA 98195.
authors.forename: Dao-Fu
authors.initials: DF
authors.lastname: Dai
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195.
authors.forename: Can
authors.initials: C
authors.lastname: Yuan
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195.
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Westenbroek
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195.
authors.forename: Haijie
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195.
authors.forename: Nastassya
authors.initials: N
authors.lastname: West
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195.
authors.forename: Horacio O
authors.initials: HO
authors.lastname: de la Iglesia
authors.affiliation: Department of Pharmacology, University of Washington, Seattle, WA 98195; wcatt@uw.edu.
authors.forename: William A
authors.initials: WA
authors.lastname: Catterall
mesh_terms: D000818:Animals; D019703:Calcineurin / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000235:genetics* / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D006332:Cardiomegaly / Q000235:genetics* / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D006321:Heart / Q000503:physiopathology; D006333:Heart Failure / Q000235:genetics* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D009043:Motor Activity; D009200:Myocardial Contraction / Q000235:genetics; D032383:Myocytes, Cardiac / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D019210:Troponin I / Q000378:metabolism; D000099211:Phospholamban
chemical_list: D019703:Calcineurin; D002118:Calcium; D020746:Calcium Channels, L-Type; D002135:Calcium-Binding Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D011943:Receptors, Adrenergic, beta; D019837:Ryanodine Receptor Calcium Release Channel; D019210:Troponin I; D000099211:Phospholamban; C514350:CACNA1C protein, mouse; C000592748:ryanodine receptor 2. mouse
keywords: PKA; calcium channel; casein kinase II; excitation–contraction coupling; heart failure