AKAP5 complex facilitates purinergic modulation of vascular L-type Ca2+ channel CaV1.2

The L-type Ca 2+ channel Ca V 1.2 is essential for arterial myocyte excitability, gene expression and contraction. Elevations in extracellular glucose (hyperglycemia) potentiate vascular L-type Ca 2+ channel via PKA, but the underlying mechanisms are unclear. Here, we find that cAMP synthesis in response to elevated glucose and the selective P2Y 11 agonist NF546 is blocked by disruption of A-kinase anchoring protein 5 (AKAP5) function in arterial myocytes. Glucose and NF546-induced potentiation of L-type Ca 2+ channels, vasoconstriction and decreased blood flow are prevented in AKAP5 null arterial myocytes/arteries. These responses are nucleated via the AKAP5-dependent clustering of P2Y 11 / P2Y 11 -like receptors, AC5, PKA and Ca V 1.2 into nanocomplexes at the plasma membrane of human and mouse arterial myocytes. Hence, data reveal an AKAP5 signaling module that regulates L-type Ca 2+ channel activity and vascular reactivity upon elevated glucose. This AKAP5-anchored nanocomplex may contribute to vascular complications during diabetic hyperglycemia. Molecular mechanisms by which glucose modulates L-type Ca 2+ channel activity and vascular reactivity are unclear. Here the authors report a nanocomplex orchestrated by AKAP5 that facilitates local purinergic stimulation of L-type Ca 2+ channels and vasoconstriction during diabetic hyperglycemia.