Martinac B, Adler J, Kung C
Laboratory of Molecular Biology, University of Wisconsin, Madison 53706.
Nature. 1990 Nov 15;348(6298):261-3. doi: 10.1038/348261a0.
Mechanosensitive channels have been found in more than 30 cell types, including bacterial, yeast, plant and animal cells. Whether tension is transferred to the channel through the lipid bilayer and/or underlying cytoskeleton is not clear. Using the patch-clamp method, we found that amphipathic compounds, which are molecules having hydrophobic and hydrophilic character with positive, negative or no net electric charge at pH 7, could slowly activate the mechanosensitive channels of giant Escherichia coli spheroplasts, with effectiveness proportional to their lipid solubility. The cationic or anionic amphipaths were able to compensate for each other's effect. After a channel was activated by an amphipath of one charge, if that amphipath was gradually replaced by one with the opposite charge, the channel first inactivated before reactivating. These findings support the view that the mechanical gating force can come from the surrounding lipids.
机械敏感通道已在30多种细胞类型中被发现，包括细菌、酵母、植物和动物细胞。张力是否通过脂质双层和/或其下的细胞骨架传递到通道尚不清楚。使用膜片钳方法，我们发现两亲性化合物（即在pH 7时具有疏水和亲水特性且净电荷为正、负或无的分子）能够缓慢激活巨大的大肠杆菌原生质球的机械敏感通道，其有效性与其脂溶性成正比。阳离子或阴离子两亲分子能够相互补偿彼此的作用。一个通道被一种电荷的两亲分子激活后，如果该两亲分子逐渐被相反电荷的两亲分子取代，通道会先失活然后再重新激活。这些发现支持了机械门控力可能来自周围脂质的观点。
