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Scaffold‐dependent stimulation of Ca V channels via C‐terminal phosphorylation promotes vasoconstriction in the diabetic vasculature
Author(s) -
Nystoriak Matthew,
NievesCintrón Madeline,
Patriarchi Tommaso,
Marotti Stefano,
Grandi Eleonora,
Dos Santos Fernandes Julia,
Forbush Katherine,
Hofmann Franz,
Ward Sean,
Scott John,
Hell Johannes,
Navedo Manuel
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1281.4
Subject(s) - vasoconstriction , myocyte , phosphorylation , medicine , endocrinology , vascular smooth muscle , microbiology and biotechnology , protein kinase a , stimulation , biology , smooth muscle
Dysregulated influx of calcium in arterial myocytes via L‐type Ca V 1.2 channels (LTCCs) has recently been linked to vascular dysfunction during diabetic hyperglycemia. Functional upregulation of LTCCs under hyperglycemic conditions involves cAMP‐dependent protein kinase (PKA) activity, yet the mechanistic details of how these pathological phenomena promote vasoconstriction is unclear. Here, we report that a subpopulation of Ca V 1.2 channels is located within nanometer proximity of PKA catalytic subunits at the sarcolemma of native murine and human arterial myocytes. This organization requires selective scaffolding of PKA RIIα by A‐kinase anchoring protein 150 (AKAP150; murine ortholog of human AKAP79). Potentiated LTCC activity in response to elevated D‐glucose was associated with enhanced phosphorylation of Ca V 1.2 at the putative PKA target site serine 1928 (S1928) in murine and human arterial myocytes, as well as in arteries from mice on a high‐fat diet (HFD) and diabetic human subjects. This modification was absent in myocytes from genetically engineered mice lacking AKAP150 or expressing mutant AKAP150 unable to target PKA. Supporting a functional role for S1928 phosphorylation, hyperglycemia‐ and HFD‐induced LTCC potentiation and vasoconstriction were nearly abolished in myocytes and arteries from mice expressing mutated Ca V 1.2 in which S1928 was replaced by alanine. These results demonstrate a requisite functional role for Ca V 1.2 S1928 phosphorylation in stimulation of vascular LTCC activity and vasoconstriction by targeted subsarcolemmal PKA signaling in hyperglycemic conditions and diabetes. Support or Funding Information This work was supported by grants from the National Institute of Health R01‐HL098200 and R01‐HL121059 and American Heart Association 14GRNT18730054 (to MFN), American Heart Association 13POST12730001 and the Lawrence J. and Florence A. DeGeorge Charitable Trust (to MAN), American Heart Association 14POST18380011 (to SM), American Heart Association Scientist Development Grant 15SDG24910015 (to EG), National Institute of Health R01‐DK54441 and R01‐DK105542 (to JDS), and National Institutes of Health R01‐MH097887 and R01‐NS078792 (to JWH).