Negative Influence by the Force: Mechanically Induced Hyperpolarization via K2P Background Potassium Channels

The two-pore domain K-2P subunits form background (leak) potassium channels, which are characterized by constitutive, although not necessarily constant activity, at all membrane potential values. Among the fifteen pore-forming K-2P subunits encoded by the KCNK genes, the three members of the TREK subfamily, TREK-1, TREK-2, and TRAAK are mechanosensitive ion channels. Mechanically induced opening of these channels generally results in outward K+ current under physiological conditions, with consequent hyperpolarization and inhibition of membrane potential-dependent cellular functions. In the past decade, great advances have been made in the investigation of the molecular determinants of mechanosensation, and members of the TREK subfamily have emerged among the best-understood examples of mammalian ion channels directly influenced by the tension of the phospholipid bilayer. In parallel, the crucial contribution of mechano-gated TREK channels to the regulation of membrane potential in several cell types has been reported. In this review, we summarize the general principles underlying the mechanical activation of K-2P channels, and focus on the physiological roles of mechanically induced hyperpolarization.

Automated summary

K-2P subunits form leak potassium channels with constitutive activity, including the mechanosensitive TREK subfamily. These channels open in response to mechanical force, leading to hyperpolarization and inhibition of cellular functions. The TREK subfamily is among the best-understood examples of mammalian ion channels influenced by phospholipid bilayer tension, crucial for regulating membrane potential in various cell types.