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AKAP150 contributes to enhanced vascular tone by facilitating large-conductance Ca2+-activated K+ channel remodeling in hyperglycemia and diabetes mellitus.

ABSTRACT: Increased contractility of arterial myocytes and enhanced vascular tone during hyperglycemia and diabetes mellitus may arise from impaired large-conductance Ca(2+)-activated K(+) (BKCa) channel function. The scaffolding protein A-kinase anchoring protein 150 (AKAP150) is a key regulator of calcineurin (CaN), a phosphatase known to modulate the expression of the regulatory BKCa ?1 subunit. Whether AKAP150 mediates BKCa channel suppression during hyperglycemia and diabetes mellitus is unknown.To test the hypothesis that AKAP150-dependent CaN signaling mediates BKCa ?1 downregulation and impaired vascular BKCa channel function during hyperglycemia and diabetes mellitus.We found that AKAP150 is an important determinant of BKCa channel remodeling, CaN/nuclear factor of activated T-cells c3 (NFATc3) activation, and resistance artery constriction in hyperglycemic animals on high-fat diet. Genetic ablation of AKAP150 protected against these alterations, including augmented vasoconstriction. d-glucose-dependent suppression of BKCa channel ?1 subunits required Ca(2+) influx via voltage-gated L-type Ca(2+) channels and mobilization of a CaN/NFATc3 signaling pathway. Remarkably, high-fat diet mice expressing a mutant AKAP150 unable to anchor CaN resisted activation of NFATc3 and downregulation of BKCa ?1 subunits and attenuated high-fat diet-induced elevation in arterial blood pressure.Our results support a model whereby subcellular anchoring of CaN by AKAP150 is a key molecular determinant of vascular BKCa channel remodeling, which contributes to vasoconstriction during diabetes mellitus.

SUBMITTER: Nystoriak MA

PROVIDER: S-EPMC3954117 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature

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