Dataset Information

Ser1928 phosphorylation by PKA stimulates the L-type Ca2+ channel CaV1.2 and vasoconstriction during acute hyperglycemia and diabetes.

ABSTRACT: Hypercontractility of arterial myocytes and enhanced vascular tone during diabetes are, in part, attributed to the effects of increased glucose (hyperglycemia) on L-type CaV1.2 channels. In murine arterial myocytes, kinase-dependent mechanisms mediate the increase in CaV1.2 activity in response to increased extracellular glucose. We identified a subpopulation of the CaV1.2 channel pore-forming subunit (?1C) within nanometer proximity of protein kinase A (PKA) at the sarcolemma of murine and human arterial myocytes. This arrangement depended upon scaffolding of PKA by an A-kinase anchoring protein 150 (AKAP150) in mice. Glucose-mediated increases in CaV1.2 channel activity were associated with PKA activity, leading to ?1C phosphorylation at Ser1928 Compared to arteries from low-fat diet (LFD)-fed mice and nondiabetic patients, arteries from high-fat diet (HFD)-fed mice and from diabetic patients had increased Ser1928 phosphorylation and CaV1.2 activity. Arterial myocytes and arteries from mice lacking AKAP150 or expressing mutant AKAP150 unable to bind PKA did not exhibit increased Ser1928 phosphorylation and CaV1.2 current density in response to increased glucose or to HFD. Consistent with a functional role for Ser1928 phosphorylation, arterial myocytes and arteries from knockin mice expressing a CaV1.2 with Ser1928 mutated to alanine (S1928A) lacked glucose-mediated increases in CaV1.2 activity and vasoconstriction. Furthermore, the HFD-induced increases in CaV1.2 current density and myogenic tone were prevented in S1928A knockin mice. These findings reveal an essential role for ?1C phosphorylation at Ser1928 in stimulating CaV1.2 channel activity and vasoconstriction by AKAP-targeted PKA upon exposure to increased glucose and in diabetes.

SUBMITTER: Nystoriak MA

PROVIDER: S-EPMC5297430 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Ser1928 phosphorylation by PKA stimulates the L-type Ca2+ channel CaV1.2 and vasoconstriction during acute hyperglycemia and diabetes.

Nystoriak Matthew A MA Nieves-Cintrón Madeline M Patriarchi Tommaso T Buonarati Olivia R OR Prada Maria Paz MP Morotti Stefano S Grandi Eleonora E Fernandes Julia Dos Santos JD Forbush Katherine K Hofmann Franz F Sasse Kent C KC Scott John D JD Ward Sean M SM Hell Johannes W JW Navedo Manuel F MF

Science signaling 20170124 463

Hypercontractility of arterial myocytes and enhanced vascular tone during diabetes are, in part, attributed to the effects of increased glucose (hyperglycemia) on L-type CaV1.2 channels. In murine arterial myocytes, kinase-dependent mechanisms mediate the increase in CaV1.2 activity in response to increased extracellular glucose. We identified a subpopulation of the CaV1.2 channel pore-forming subunit (α1C) within nanometer proximity of protein kinase ...[more]

PMID: 28119464

Similar Datasets

Project description:RATIONALE:Large-conductance calcium-activated potassium channels (BK) are composed of pore-forming BK? and auxiliary ?1 subunits in arterial smooth muscle cells (myocytes). Vasoconstrictors, including endothelin-1 (ET-1), inhibit myocyte BK channels, leading to contraction, but mechanisms involved are unclear. Recent evidence indicates that BK? is primarily plasma membrane localized, whereas the cellular location of ?1 can be rapidly altered by Rab11A-positive recycling endosomes. Whether vasoconstrictors regulate the multisubunit composition of surface BK channels to stimulate contraction is unclear. OBJECTIVE:Test the hypothesis that ET-1 inhibits BK channels by altering BK? and ?1 surface trafficking in myocytes, identify mechanisms involved, and determine functional significance in myocytes of small cerebral arteries. METHODS AND RESULTS:ET-1, through activation of PKC (protein kinase C), reduced surface ?1 abundance and the proximity of ?1 to surface BK? in myocytes. In contrast, ET-1 did not alter surface BK?, total ?1, or total BK? proteins. ET-1 stimulated Rab11A phosphorylation, which reduced Rab11A activity. Rab11A serine 177 was identified as a high-probability PKC phosphorylation site. Expression of a phosphorylation-incapable Rab11A construct (Rab11A S177A) blocked the ET-1-induced Rab11A phosphorylation, reduction in Rab11A activity, and decrease in surface ?1 protein. ET-1 inhibited single BK channels and transient BK currents in myocytes and stimulated vasoconstriction via a PKC-dependent mechanism that required Rab11A S177. In contrast, NO-induced Rab11A activation, surface trafficking of ?1 subunits, BK channel and transient BK current activation, and vasodilation did not involve Rab11A S177. CONCLUSIONS:ET-1 stimulates PKC-mediated phosphorylation of Rab11A at serine 177, which inhibits Rab11A and Rab11A-dependent surface trafficking of ?1 subunits. The decrease in surface ?1 subunits leads to a reduction in BK channel calcium-sensitivity, inhibition of transient BK currents, and vasoconstriction. We describe a unique mechanism by which a vasoconstrictor inhibits BK channels and identify Rab11A serine 177 as a modulator of arterial contractility.

Project description:Mice with smooth muscle (SM)-specific knockout of Na(+)/Ca(2+) exchanger type-1 (NCX1(SM-/-)) and the NCX inhibitor, SEA0400, were used to study the physiological role of NCX1 in mouse mesenteric arteries. NCX1 protein expression was greatly reduced in arteries from NCX1(SM-/-) mice generated with Cre recombinase. Mean blood pressure (BP) was 6-10 mmHg lower in NCX1(SM-/-) mice than in wild-type (WT) controls. Vasoconstriction was studied in isolated, pressurized mesenteric small arteries from WT and NCX1(SM-/-) mice and in heterozygotes with a global null mutation (NCX1(Fx/-)). Reduced NCX1 activity was manifested by a marked attenuation of responses to low extracellular Na(+) concentration, nanomolar ouabain, and SEA0400. Myogenic tone (MT, 70 mmHg) was reduced by approximately 15% in NCX1(SM-/-) arteries and, to a similar extent, by SEA0400 in WT arteries. MT was normal in arteries from NCX1(Fx/-) mice, which had normal BP. Vasoconstrictions to phenylephrine and elevated extracellular K(+) concentration were significantly reduced in NCX1(SM-/-) arteries. Because a high extracellular K(+) concentration-induced vasoconstriction involves the activation of L-type voltage-gated Ca(2+) channels (LVGCs), we measured LVGC-mediated currents and Ca(2+) sparklets in isolated mesenteric artery myocytes. Both the currents and the sparklets were significantly reduced in NCX1(SM-/-) (vs. WT or NCX1(Fx/-)) myocytes, but the voltage-dependent inactivation of LVGCs was not augmented. An acute application of SEA0400 in WT myocytes had no effect on LVGC current. The LVGC agonist, Bay K 8644, eliminated the differences in LVGC currents and Ca(2+) sparklets between NCX1(SM-/-) and control myocytes, suggesting that LVGC expression was normal in NCX1(SM-/-) myocytes. Bay K 8644 did not, however, eliminate the difference in myogenic constriction between WT and NCX1(SM-/-) arteries. We conclude that, under physiological conditions, NCX1-mediated Ca(2+) entry contributes significantly to the maintenance of MT. In NCX1(SM-/-) mouse artery myocytes, the reduced Ca(2+) entry via NCX1 may lower cytosolic Ca(2+) concentration and thereby reduce MT and BP. The reduced LVGC activity may be the consequence of a low cytosolic Ca(2+) concentration.

Dataset Information

Ser1928 phosphorylation by PKA stimulates the L-type Ca2+ channel CaV1.2 and vasoconstriction during acute hyperglycemia and diabetes.

Publications

Ser1928 phosphorylation by PKA stimulates the L-type Ca2+ channel CaV1.2 and vasoconstriction during acute hyperglycemia and diabetes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets