Mechanosensitive Channels Gated by Membrane Tension

Abstract

What are the stimuli that are sensed by mechanoreceptors? Researchers have now begun to address this question and determine the molecular mechanisms underlying channels that are gated by mechanical forces. Two quite different models now exist. The first is that the channels are ‘tethered’ to cytoskeleton and or extracellular components, which thus exert forces on the channel that lead to gating. The second model predicts that the channel protein directly senses biophysical changes that occur within the membrane when it is under tension. Several lines of evidence indicate that many putative mechanosensitive channels are indeed tethered by other proteins, however in many instances the exact role this tethering plays in mechanosensing has yet to be fully clarified. On the other hand, the cloning and study of bacterial mechanosensitive channels demonstrated that channels can directly sense tension within the membrane. Evidence obtained from several of the more complex eukaryotic mechanosensory systems suggests that a number of eukaryotic channels from divergent families similarly sense tension within the membrane.