REGULATION OF THE GATING OF CYSTIC-FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR CL CHANNELS BY PHOSPHORYLATION AND ATP HYDROLYSIS
REGULATION OF THE GATING OF CYSTIC-FIBROSIS TRANSMEMBRANE CONDUCTANCE REGULATOR CL CHANNELS BY PHOSPHORYLATION AND ATP HYDROLYSIS
复制标题
DOI：
10.1073/pnas.91.11.4698
复制
发表时间：
1994-05-24
影响因子：
11.1
通讯作者：
GADSBY, DC
中科院分区：
文献类型：
--
作者：
HWANG, TC;NAGEL, G;GADSBY, DC
囊性纤维化跨膜传导调节因子（CFTR）Cl通道的开放需要它们被蛋白激酶A磷酸化，然后暴露于ATP。我们研究了核苷酸和磷酸化CFTR通道之间的相互作用，记录电流在完整的心肌细胞和切除的补丁。我们发现，尽管抗水解ATP类似物5 '-腺苷（β，γ-亚氨基）三磷酸（AMP-PNP）不能打开磷酸化CFTR通道，但它可以使ATP打开的通道保持开放许多分钟。这表明ATP在CFTR上的一个位点的作用是AMP-PNP在第二位点作用的先决条件。然而，AMP-PNP的这种作用仅限于高度磷酸化的CFTR通道，其在ATP存在下显示出相对高的开放概率，但在部分磷酸化的CFTR通道中看不到，其在ATP存在下具有低的开放概率。我们的研究结果表明，增量磷酸化差异调节核苷酸和CFTR的两个核苷酸结合结构域之间的相互作用。这些相互作用的性质表明，ATP水解在一个核苷酸结合域控制通道开放和ATP水解在其他调节通道关闭。
Opening of cystic fibrosis transmembrane conductance regulator (CFTR) CI channels requires their phosphorylation by protein kinase A followed by exposure to ATP. We examined the interaction between nucleotides and phosphorylated CFTR channels by recording currents in intact cardiac myocytes and in excised patches. We found that, although the hydrolysis-resistant ATP analogue 5'-adenosine(beta,gamma-imino)triphosphate (AMP-PNP) cannot open phosphorylated CFTR channels, it can cause channels opened by ATP to remain open for many minutes. This suggests that ATP action at one site on CFTR is a prerequisite for AMP-PNP action at a second site. However, this action of AMP-PNP is restricted to highly phosphorylated CFTR channels, which, in the presence of ATP, display a relatively high open probability, but is not seen in partially phosphorylated CFTR channels, which have a low open probability in the presence of ATP. Our findings argue that incremental phosphorylation differentially regulates the interactions between nucleotides and the two nucleotide binding domains of CFTR. The nature of those interactions suggests that ATP hydrolysis at one nucleotide binding domain controls channel opening and ATP hydrolysis at the other regulates channel closing.