PKC regulation of cardiac CFTR Cl- channel function in guinea pig ventricular myocytes.
PKC regulation of cardiac CFTR Cl- channel function in guinea pig ventricular myocytes.
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PKC 对豚鼠心室肌细胞 CFTR Cl 通道功能的调节。
DOI：
10.1152/ajpcell.1998.275.1.c293
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Harvey,RD
中科院分区：
文献类型：
--
作者：
Middleton,LM;Harvey,RD
采用全细胞膜片钳技术研究了蛋白激酶C（PKC）对豚鼠心室肌细胞中囊性纤维化跨膜传导调节因子（cCFTR）心脏亚型介导的蛋白激酶A（PKA）激活的Cl−电流的调节作用。尽管单独用佛波醇12，13-二丁酸酯（PDBu）刺激内源性PKC并不能激活这种Cl−电流，即使用穿孔膜片钳技术限制细胞内透析，PKC的激活在β-肾上腺素能受体激动剂异丙肾上腺素对电流的PKA依赖性激活存在下也确实引起了显著的反应。当在异丙肾上腺素之后加入PDBu时，PDBu使由超最大刺激浓度的异丙肾上腺素激活的Cl−电导增加21 ± 3.3%（n= 9），当在异丙肾上腺素之前加入PDBu时，PDBu使其增加36 ± 16%（n= 14）。4α-佛波醇12，13-二癸酸酯，一种不激活PKC的佛波醇酯，没有模拟这些作用。预先暴露于白屈菜红碱或双吲哚马来酰亚胺（两种高度选择性的PKC抑制剂），可显著降低异丙肾上腺素激活的Cl−电流幅度，分别为79 ± 7.7%（n= 11）和52 ± 10%（n= 8）。我们的研究结果表明，虽然内源性PKC单独急性激活并不显着调节天然心肌细胞中的cCFTR Cl−通道活性，但它确实增强了PKC依赖性反应，可能最显着地表现为基础PKC活性，这可能在调节这些通道的功能中发挥关键作用。
The role of protein kinase C (PKC) in regulating the protein kinase A (PKA)-activated Cl−current conducted by the cardiac isoform of the cystic fibrosis transmembrane conductance regulator (cCFTR) was studied in guinea pig ventricular myocytes using the whole cell patch-clamp technique. Although stimulation of endogenous PKC with phorbol 12,13-dibutyrate (PDBu) alone did not activate this Cl−current, even when intracellular dialysis was limited with the perforated patch-clamp technique, activation of PKC did elicit a significant response in the presence of PKA-dependent activation of the current by the β-adrenergic receptor agonist isoproterenol. PDBu increased the magnitude of the Cl−conductance activated by a supramaximally stimulating concentration of isoproterenol by 21 ± 3.3% (n= 9) when added after isoproterenol and by 36 ± 16% (n= 14) when introduced before isoproterenol. 4α-Phorbol 12,13-didecanoate, a phorbol ester that does not activate PKC, did not mimic these effects. Preexposure to chelerythrine or bisindolylmaleimide, two highly selective inhibitors of PKC, significantly reduced the magnitude of the isoproterenol-activated Cl−current by 79 ± 7.7% (n= 11) and 52 ± 10% (n= 8), respectively. Our results suggest that although acute activation of endogenous PKC alone does not significantly regulate cCFTR Cl−channel activity in native myocytes, it does potentiate PKA-dependent responses, perhaps most dramatically demonstrated by basal PKC activity, which may play a pivotal role in modulating the function of these channels.