Mechanosensitive Ion Channels in Bacteria

Abstract

Mechanosensitive ion channels are a class of ion channels which transduce mechanical forces of the cell membrane into an electrical response. These channels are gated by the mechanical force produced by stretching the lipid bilayer and/or the underlying cytoskeleton of cell membranes. They were initially reported by Guharay and Sachs (1984) in chick skeletal muscle and nearly simultaneously by Brehm et al. in embryonic Xenopus muscle (Brehm et al. 1984). They are now found in a variety of animal and plant tissues (Ohmori 1984; Brezden et al. 1986; Cooper et al. 1986; Sigurdson et al. 1987; Falke et al. 1988), as well as in fungi (Gustin et al. 1988) and bacteria (Martinac et al. 1987; Zoratti and Petronilli 1988; Berner et al. 1989). The mechanosensitive channels appear ubiquitous. The only class of animal cells which seem to lack them are undifferentiated cancer cell lines (Sachs 1988). Mechanosensitive ion channels have been suggested to play important physiological roles (touch, hearing, proprioception) in many systems (Sachs 1988). Regulation of cell volume, osmolality, and growth are also among the processes which are likely to be controlled by these channels.