ABCC9 p.Gln52Asp
| Predicted by SNAP2: | A: N (66%), C: D (59%), D: D (80%), E: N (53%), F: D (53%), G: D (53%), H: N (72%), I: D (53%), K: N (87%), L: N (61%), M: D (59%), N: N (57%), P: N (61%), R: N (82%), S: N (72%), T: N (78%), V: D (59%), W: D (66%), Y: N (66%), |
| Predicted by PROVEAN: | A: N, C: N, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, N: N, P: N, R: N, S: N, T: N, V: N, W: N, Y: N, |
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[hide] Hypotension due to Kir6.1 gain-of-function in vasc... J Am Heart Assoc. 2013 Aug 23;2(4):e000365. doi: 10.1161/JAHA.113.000365. Li A, Knutsen RH, Zhang H, Osei-Owusu P, Moreno-Dominguez A, Harter TM, Uchida K, Remedi MS, Dietrich HH, Bernal-Mizrachi C, Blumer KJ, Mecham RP, Koster JC, Nichols CG
Hypotension due to Kir6.1 gain-of-function in vascular smooth muscle.
J Am Heart Assoc. 2013 Aug 23;2(4):e000365. doi: 10.1161/JAHA.113.000365., [PMID:23974906]
Abstract [show]
BACKGROUND: KATP channels, assembled from pore-forming (Kir6.1 or Kir6.2) and regulatory (SUR1 or SUR2) subunits, link metabolism to excitability. Loss of Kir6.2 results in hypoglycemia and hyperinsulinemia, whereas loss of Kir6.1 causes Prinzmetal angina-like symptoms in mice. Conversely, overactivity of Kir6.2 induces neonatal diabetes in mice and humans, but consequences of Kir6.1 overactivity are unknown. METHODS AND RESULTS: We generated transgenic mice expressing wild-type (WT), ATP-insensitive Kir6.1 [Gly343Asp] (GD), and ATP-insensitive Kir6.1 [Gly343Asp,Gln53Arg] (GD-QR) subunits, under Cre-recombinase control. Expression was induced in smooth muscle cells by crossing with smooth muscle myosin heavy chain promoter-driven tamoxifen-inducible Cre-recombinase (SMMHC-Cre-ER) mice. Three weeks after tamoxifen induction, we assessed blood pressure in anesthetized and conscious animals, as well as contractility of mesenteric artery smooth muscle and KATP currents in isolated mesenteric artery myocytes. Both systolic and diastolic blood pressures were significantly reduced in GD and GD-QR mice but normal in mice expressing the WT transgene and elevated in Kir6.1 knockout mice as well as in mice expressing dominant-negative Kir6.1 [AAA] in smooth muscle. Contractile response of isolated GD-QR mesenteric arteries was blunted relative to WT controls, but nitroprusside relaxation was unaffected. Basal KATP conductance and pinacidil-activated conductance were elevated in GD but not in WT myocytes. CONCLUSIONS: KATP overactivity in vascular muscle can lead directly to reduced vascular contractility and lower blood pressure. We predict that gain of vascular KATP function in humans would lead to a chronic vasodilatory phenotype, as indeed has recently been demonstrated in Cantu syndrome.
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No. Sentence Comment
204 It is also noteworthy that glibenclamide inhibition of these currents is less than the glibenclamide inhibition of WT channels, again reflective of the loss of sulfonylurea sensitivity documented for the open-state stabilizing Gln52Asp mutation in Kir6.2.20 Vascular KATP and Blood Pressure Control KATP channels are presumed to be tonically active in many vascular beds, and hence to play a role in establishing basal vessel tone, based on glibenclamide-induced depolarization and constriction, both in isolated arteries and in vivo.35 Pharmacological activation of KATP channels typically leads to a lowering of intracellular Ca2+ levels, increase in arteriole diameter, and decrease in vascular resistance,2 but the exact target of such activators is not always clear.
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ABCC9 p.Gln52Asp 23974906:204:227
status: NEW