Sensing pressure with ion channels.

Opening of stretch-activated ion channels (SACs) is the earliest event occurring in mechanosensory transduction. The molecular identity of mammalian SACs has long remained a mystery. Only very recently, Piezo1 and Piezo2 have been shown to be essential components of distinct SACs and moreover, purified Piezo1 forms cationic channels when reconstituted into artificial bilayers. In line with these findings, dPiezo was demonstrated to act in the Drosophila mechanical nociception pathway. Finally, the 3D structure of the two-pore domain potassium channel (K(2P)), TRAAK [weakly inward rectifying K⁺ channel (TWIK)-related arachidonic acid stimulated K⁺ channel], has recently been solved, providing valuable information about pharmacology, selectivity and gating mechanisms of stretch-activated K⁺ channels (SAKs). These recent findings allow a better understanding of the molecular basis of molecular and cellular mechanotransduction.