Mutation of protein kinase C phosphorylation site S1076 on alpha-subunits affects BK(Ca) channel activity in HEK-293 cells.
Mutation of protein kinase C phosphorylation site S1076 on alpha-subunits affects BK(Ca) channel activity in HEK-293 cells.
复制标题
α 亚基上蛋白激酶 C 磷酸化位点 S1076 的突变影响 HEK-293 细胞中的 BK(Ca) 通道活性。
DOI：
10.1152/ajplung.90518.2008
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Barman,ScottA
中科院分区：
文献类型：
--
作者：
Zhu,Shu;Browning,DarrenD;White,RichardE;Fulton,David;Barman,ScottA
大电导、钙离子和电压激活的钾离子通道（BKCa）是肺血管平滑肌膜电位的重要调节剂，通过蛋白激酶磷酸化BKCa通道调节肺动脉平滑肌功能。然而，很少有人知道磷酸化特定通道亚基对BKCa通道活性的影响。本研究在人胚肾（HEK-293）细胞中检测突变蛋白激酶C（PKC）磷酸化位点丝氨酸1076（S1076）对转染的人BKCa通道α亚基的影响。结果表明，突变S1076改变了PKC激活对HEK-293细胞BKC通道的影响。磷酸化缺陷突变BKCa-α（S1076 A）/β 1减弱了PKC激活剂佛波酯（PMA）对BKCa通道的兴奋作用，而磷酸化模拟突变BKCa-α（S1076 E）/β 1增强了PMA对BKCa通道的兴奋作用。此外，磷酸无效突变S1076 A阻断cGMP依赖性蛋白激酶G（PKG）对BKC通道的激活作用。总的来说，这些结果表明，人BKC通道α亚基上特定的推定PKC磷酸化位点影响BKC通道活性，这可能随后改变肺血管平滑肌功能和张力。
Large conductance, calcium- and voltage-activated potassium (BKCa) channels are important modulators of pulmonary vascular smooth muscle membrane potential, and phosphorylation of BKCachannels by protein kinases regulates pulmonary arterial smooth muscle function. However, little is known about the effect of phosphorylating specific channel subunits on BKCachannel activity. The present study was done to determine the effect of mutating protein kinase C (PKC) phosphorylation site serine 1076 (S1076) on transfected human BKCachannel α-subunits in human embryonic kidney (HEK-293) cells, a heterologous expression system devoid of endogenous BKCachannels. Results showed that mutating S1076 altered the effect of PKC activation on BKCachannels in HEK-293 cells. Specifically, the phospho-deficient mutation BKCa-α(S1076A)/β1attenuated the excitatory effect of the PKC activator phorbol myristate acetate (PMA) on BKCachannels, whereas the phospho-mimetic mutation BKCa-α(S1076E)/β1increased the excitatory effect of PMA on BKCachannels. In addition, the phospho-null mutation S1076A blocked the activating effect of cGMP-dependent protein kinase G (PKG) on BKCachannels. Collectively, these results suggest that specific putative PKC phosphorylation site(s) on human BKCachannel α-subunits influences BKCachannel activity, which may subsequently alter pulmonary vascular smooth muscle function and tone.