In vivo phosphorylation of the epithelial sodium channel
In vivo phosphorylation of the epithelial sodium channel
复制标题
DOI：
10.1073/pnas.95.6.3301
复制
发表时间：
1998-03-17
影响因子：
11.1
通讯作者：
Canessa, CM
中科院分区：
文献类型：
--
作者：
Shimkets, RA;Lifton, R;Canessa, CM
远端肾单位上皮钠通道(ENaC)的活性受抗利尿激素、醛固酮和胰岛素的调节，但调节这些激素效应的分子机制大多尚不清楚。我们已经研究了醛固酮、胰岛素或蛋白激酶的激活是否对通道的磷酸化有影响。实验是在ENaC的三个亚单位(α、β和γ)稳定共转染产生的上皮细胞系中进行的。我们发现，在基础状态下，β亚基和伽马亚基被磷酸化，而阿尔法亚单位却没有。醛固酮、胰岛素以及蛋白激酶A和C增加了其羧基末端的β和伽马亚基的磷酸化，但这些药物都没有诱导α亚基的从头磷酸化。丝氨酸和苏氨酸被发现是磷酸化的，而不是酪氨酸。结果表明，醛固酮、胰岛素和蛋白激酶A和C通过磷酸化β和伽马亚基的羧基末端来调节ENaC的活性。
The activity of the epithelial sodium channel (ENaC) in the distal nephron is regulated by an antidiuretic hormone, aldosterone, and insulin, but the molecular mechanisms that mediate these hormonal effects are mostly unknown. We have investigated whether aldosterone, insulin, or activation of protein kinases has an effect on the phosphorylation of the channel. Experiments were performed in an epithelial cell line generated by stable cotransfection of the three subunits (alpha, beta, and gamma) of ENaC. We found that beta and gamma, but not the alpha subunit, are phosphorylated in the basal state. Aldosterone, insulin, and protein kinases A and C increased phosphorylation of the beta and gamma subunits in their carboxyl termini, but none of these agents induced de novo phosphorylation of alpha subunits. Serines and threonines but not tyrosines were found to be phosphorylated. The results suggest that aldosterone, insulin, and protein kinases A and C modulate the activity of ENaC by phosphorylation of the carboxyl termini of the beta and gamma subunits.