Regulation of a human chloride channel - A paradigm for integrating input from calcium, type II calmodulin-dependent protein kinase, and inositol 3,4,5,6-tetrakisphosphate
Regulation of a human chloride channel - A paradigm for integrating input from calcium, type II calmodulin-dependent protein kinase, and inositol 3,4,5,6-tetrakisphosphate
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DOI：
10.1074/jbc.m101128200
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发表时间：
2001-06-01
影响因子：
4.8
通讯作者：
Shears, SB
中科院分区：
文献类型：
--
作者：
Ho, MWY;Kaetzel, MA;Shears, SB
我们研究了人胰腺瘤上皮细胞系（CFPAC-1）中钙离子依赖性氯离子（Cl-Ca）通道的调节，该细胞系不表达功能性cAMP依赖性囊性纤维化跨膜电导调节剂氯离子通道。在这些细胞的无细胞补丁，生理Ca 2+浓度激活一类1皮西门子Cl-选择性通道。同样的通道也刺激了纯化的II型钙调蛋白依赖性蛋白激酶（CaMKII），并在细胞附着的补丁嘌呤激动剂。在全细胞记录中，Ca 2+和CaMK II依赖性机制都有助于Ca 2+对氯离子通道的刺激，但CaMK II依赖性途径被肌醇3，4，5，6-四磷酸（Ins（3，4，5，6）P-4）选择性抑制。Ins（3，4，5，6）P对CaMKII刺激的Cl-Ca通道的抑制作用可通过升高[Ca 2 +]而降低，并可通过用100 nM冈田酸抑制蛋白磷酸酶活性而防止。这些数据为理解Ins（3，4，5，6）P在上皮细胞中Ca 2+依赖性Cl-通量的长期调节中的生理相关性提供了新的背景。
We have studied the regulation of Ca2+-dependent chloride (Cl-Ca) channels in a human pancreatoma epithelial cell line (CFPAC-1), which does not express functional cAMP-dependent cystic fibrosis transmembrane conductance regulator chloride channels. In cell-free patches from these cells, physiological Ca2+ concentrations activated a single class of 1-picosiemens Cl--selective channels. The same channels were also stimulated by a purified type II calmodulin-dependent protein kinase (CaMKII), and in cell-attached patches by purinergic agonists. In whole-cell recordings, both Ca2+- and CaMKII-dependent mechanisms contributed to chloride channel stimulation by Ca2+, but the CaMKII-dependent pathway was selectively inhibited by inositol 3,4,5,6-tetrakisphosphate (Ins(3,4,5,6)P-4). This inhibitory effect of Ins(3,4,5,6)P, on Cl-Ca channel stimulation by CaMKII was reduced by raising [Ca2+] and prevented by inhibition of protein phosphatase activity with 100 nM okadaic acid. These data provide a new context for understanding the physiological relevance of Ins(3,4,5,6)P, in the longer term regulation of Ca2+-dependent Cl- fluxes in epithelial cells.