Connexins are mechanosensitive
Connexins are mechanosensitive
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DOI：
10.1152/ajpcell.00220.2004
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发表时间：
2004-11-01
影响因子：
5.5
通讯作者：
Dahl, G
中科院分区：
文献类型：
--
作者：
Bao, L;Sachs, F;Dahl, G
连接蛋白形成间隙连接通道，其在细胞内部之间提供亲水路径。一些连接蛋白，特别是透镜连接蛋白，Cx46和Cx50及其直系同源物，可以在非连接膜中形成功能性半通道。这些半通道是通向细胞外介质的非选择性管道，并且可能危及细胞存活。半通道的生理功能仍然是难以捉摸的，但它已被假定，半通道参与ATP释放引起的机械刺激。在这里，我们显示与单通道和全细胞电生理研究，Cx46半通道是机械敏感的，像其他家庭的离子通道和膜结合酶。半通道对机械应力的反应是双极的。在负电位时，应力打开通道，而在正电位时，应力关闭通道。生理上，Cx46半通道可通过在透镜改变形状时提供体积流的瞬时路径来辅助眼透镜的调节。
Connexins form gap junction channels that provide a hydrophilic path between cell interiors. Some connexins, particularly the lens connexins, Cx46 and Cx50 and their orthologs, can form functional hemichannels in nonjunctional membranes. These hemichannels are a nonselective conduit to the extracellular medium and may jeopardize cell survival. The physiological function of hemichannels has remained elusive, but it has been postulated that hemichannels are involved in ATP-release caused by mechanical stimulation. Here we show with single-channel and whole cell electrophysiological studies that Cx46 hemichannels are mechanosensitive, like other families of ion channels and membrane-bound enzymes. The hemichannel response to mechanical stress is bipolar. At negative potentials stress opens the channel, and at positive potentials stress closes it. Physiologically, Cx46 hemichannels may assist accommodation of the ocular lens by providing a transient path for volume flow as the lens changes shape.