Nerve growth factor-induced endocytosis of TWIK-related acid-sensitive K+ 1 channels in adrenal medullary cells and PC12 cells
Nerve growth factor-induced endocytosis of TWIK-related acid-sensitive K+ 1 channels in adrenal medullary cells and PC12 cells
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神经生长因子诱导肾上腺髓质细胞和 PC12 细胞 TWIK 相关酸敏感 K 1 通道的内吞作用
DOI：
10.1007/s00424-013-1222-3
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Inoue M
中科院分区：
文献类型：
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作者：
Matsuoka H;Harada K;Nakamura J;Inoue M
TWIK相关酸敏K+(TASK)通道属于两孔结构域K+通道家族，可产生背景K+电流，参与酸中毒检测等重要生理功能。我们最近阐明，TASK1样通道是大鼠肾上腺髓质(AM)细胞的酸中毒感受器，对AM细胞的内分泌功能是不可或缺的。在这里，我们利用药理学、电生理学和生物化学的方法，研究了TASK1通道在大鼠AM细胞和PC12细胞中的表达和定位。PC12细胞不仅表达TASK1通道，而且还表达TASK3通道，它们不构成异源二聚体。AM细胞和PC12细胞暴露于神经生长因子(NGF)可诱导TASK1通道内吞，但不能诱导TASK3通道内吞，这种作用依赖于细胞骨架蛋白。对TASK1通道的突变分析表明，二亮氨酸基序(LL263/264)至少参与了部分内吞作用。将表达GFP-TASK1的PC12细胞接种到成纤维细胞上，产生NGF，导致GFP-TASK1通道的内吞。此外，NGF处理PC12细胞2周后，TASK1通道在蛋白和mRNA水平的表达均受到抑制。这些结果表明，NGF不仅通过内吞作用抑制质膜TASK1通道的表达，而且还通过抑制基因转录来抑制TASK1通道的表达。因此，NO对NGF的访问可能在AM细胞细胞膜TASK1通道的维持中起主要作用。
TWIK-related acid-sensitive K+(TASK) channels belong to a family of two-pore domain K+channels which produce background K+currents and are involved in important physiological functions, such as acidosis detection. We have recently elucidated that TASK1-like channels function as a sensor of acidosis in rat adrenal medullary (AM) cells and thus are indispensable for the endocrine function of AM cells. Here, using pharmacological, electrophysiological and biochemical methods, we studied how the expression and localisation of TASK1 channels are regulated in rat AM cells and PC12 cells. PC12 cells were found to express not only TASK1 but also TASK3 channels, and they did not constitute a heterodimer. The exposure of AM cells and PC12 cells to nerve growth factor (NGF) induced endocytosis of TASK1, but not TASK3 channels, in a clathrin-dependent manner. Mutation analysis of the TASK1 channel revealed that the dileucine motif (LL263/264) was involved in at least part of the endocytosis. Plating GFP-TASK1-expressing PC12 cells onto a sheet of fibroblasts, which produced NGF, resulted in the endocytosis of GFP-TASK1 channels. Additionally, the expression of TASK1 channels at the protein and mRNA levels was suppressed in PC12 cells treated with NGF for 2 weeks. These results indicate that NGF suppresses the expression of TASK1 channels in the plasma membrane via not only endocytosis but also the inhibition of gene transcription. Thus, no access to NGF may play a major role for the maintenance of TASK1 channels in the cell membrane in AM cells.