Molecular basis for the modulation of native T-type Ca2+ channels in vivo by Ca2+/calmodulin-dependent protein kinase II.
Ang II receptor activation increases cytosolic Ca2+ levels to enhance the synthesis and secretion of aldosterone, a recently identified early pathogenic stimulus that adversely influences cardiovascular homeostasis. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a downstream effector of the Ang II-elicited signaling cascade that serves as a key intracellular Ca2+ sensor to feedback-regulate Ca2+ entry through voltage-gated Ca2+ channels. However, the molecular mechanism(s) by which CaMKII regulates these important physiological targets to increase Ca2+ entry remain unresolved. We show here that CaMKII forms a signaling complex with alpha1H T-type Ca2+ channels, directly interacting with the intracellular loop connecting domains II and III of the channel pore (II-III loop). Activation of the kinase mediated the phosphorylation of Ser1198 in the II-III loop and the positive feedback regulation of channel gating both in intact cells in situ and in cells of the native adrenal zona glomerulosa stimulated by Ang II in vivo. These data define the molecular basis for the in vivo modulation of native T-type Ca2+ channels by CaMKII and suggest that the disruption of this signaling complex in the zona glomerulosa may provide a new therapeutic approach to limit aldosterone production and cardiovascular disease progression.
Yao
Junlan
J
Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
Davies
Lucinda A
LA
Howard
Jason D
JD
Adney
Scott K
SK
Welsby
Philip J
PJ
Howell
Nancy
N
Carey
Robert M
RM
Colbran
Roger J
RJ
Barrett
Paula Q
PQ
D001483:Base Sequence; D020747:Calcium Channels, T-Type / Q000502:physiology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D017931:DNA Primers; D004789:Enzyme Activation; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology; D007668:Kidney; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
D020747:Calcium Channels, T-Type; D017931:DNA Primers; D011994:Recombinant Proteins; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases