Stretchactivated

Stretch-activated channels are ion channels that open in response to mechanical deformation of the cell membrane, such as stretch, tension, or shear. They are found across bacteria, plants, and animals and typically mediate rapid ion fluxes that alter membrane potential and intracellular signaling, often via calcium.

Gating is thought to arise from changes in membrane tension that modulate channel conformation. Some channels are gated by the lipid bilayer itself (lipid gating), while others are tethered to the cytoskeleton or extracellular matrix, providing additional mechanical cues that influence opening and closing.

Notable stretch-activated channels include bacterial MscL and MscS that protect against osmotic lysis; plant OSCA channels; animal Piezo1 and Piezo2, which mediate touch and proprioception; and nematode MEC-4/MEC-10 and Drosophila NOMPC, involved in mechanosensation. These channels illustrate the diversity of mechanosensitive gating across kingdoms and tissue types.

Physiological roles are diverse: in mammals they contribute to touch and proprioception, vascular responses to shear stress, and hearing and balance; in other organisms they participate in osmoregulation and cell volume regulation. Dysfunction or mutations in mechanosensitive channels can contribute to disease, and these channels are active areas of research for pain, hypertension, and sensory disorders.

Advances in structural biology, particularly cryo-electron microscopy, have revealed the architectures of several stretch-activated channels, aiding understanding of gating mechanisms. Ongoing work seeks to resolve how different mechanical cues are integrated with cellular and tissue mechanics to produce physiological responses.