The Purified Mechanosensitive Channel TREK-1 Is Directly Sensitive to Membrane Tension
The Purified Mechanosensitive Channel TREK-1 Is Directly Sensitive to Membrane Tension
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DOI：
10.1074/jbc.m113.478321
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发表时间：
2013-09-20
影响因子：
4.8
通讯作者：
Ghazi, Alexandre
中科院分区：
文献类型：
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作者：
Berrier, Catherine;Pozza, Alexandre;Ghazi, Alexandre
机械敏感通道存在于所有细胞中，据推测在渗透调节、生长、听力、平衡和触觉等许多功能中发挥关键作用。在原核细胞中，由于纯化的通道可以在脂质双分子层中功能重建，因此可以通过膜张力直接门控机械敏感通道。在动物细胞的机械敏感通道中还没有这样的证据。TREK-1是一个双孔结构域的K+通道，是第一个在分子水平上发现的动物机械敏感通道。它是多种药物的靶点，如挥发性麻醉剂、神经保护剂和抗抑郁药。我们在酵母中产生了小鼠TREK-1，纯化了它，并在适合膜片钳记录的巨型脂质体中重组了蛋白质。该蛋白在动力学、选择性和药理学方面表现出预期的电生理特性。通过移液器施加的负压（吸力）对通道没有影响，而正压可以完全可逆地关闭通道。我们对这些数据的解释是，脂质双分子层的固有张力足以最大限度地激活通道，并且可以在张力改变后关闭通道。这些结果表明TREK-1对膜张力直接敏感。
Mechanosensitive channels are detected in all cells and are speculated to play a key role in many functions including osmoregulation, growth, hearing, balance, and touch. In prokaryotic cells, a direct gating of mechanosensitive channels by membrane tension was clearly demonstrated because the purified channels could be functionally reconstituted in a lipid bilayer. No such evidence has been presented yet in the case of mechanosensitive channels from animal cells. TREK-1, a two-pore domain K+ channel, was the first animal mechanosensitive channel identified at the molecular level. It is the target of a large variety of agents such as volatile anesthetics, neuroprotective agents, and antidepressants. We have produced the mouse TREK-1 in yeast, purified it, and reconstituted the protein in giant liposomes amenable to patch clamp recording. The protein exhibited the expected electrophysiological properties in terms of kinetics, selectivity, and pharmacology. Negative pressure (suction) applied through the pipette had no effect on the channel, but positive pressure could completely and reversibly close the channel. Our interpretation of these data is that the intrinsic tension in the lipid bilayer is sufficient to maximally activate the channel, which can be closed upon modification of the tension. These results indicate that TREK-1 is directly sensitive to membrane tension.