InterPro domain: IPR036019

Mechanosensitive ion channels (MscL) play a critical role in transducing physical stresses at the cell membrane into an electrochemical response. MscL is a protein which forms a channel organised as a homopentamer, with each subunit containing two transmembrane regions [ 1 , 2 , 3 ]. Prokaryotes harbor a large-conductance mechanosensitive channel (gene mscL) that opens in response to stretch forces in the membrane lipid bilayer and participate in the regulation of osmotic pressure changes within the cell [ 4 ]. MscL has a conserved domain architecture which comprises an amphipathic alpha-helix (S1) that lies along the cytoplasmic membrane, a highly conserved first transmembrane domain (TM1) that forms the pore constriction, a periplasmic loop, a second transmembrane domain (TM2) that faces the lipid membrane, and a linker that leads to a cytoplasmic alpha-helical bundle [ 5 ].

1. Structure of the MscL homolog from Mycobacterium tuberculosis: a gated mechanosensitive ion channel. Science 282, 2220-6
2. Structure of a tetrameric MscL in an expanded intermediate state. Nature 461, 120-4
3. The MscS and MscL families of mechanosensitive channels act as microbial emergency release valves. J Bacteriol 194, 4802-9
4. Functional and structural conservation in the mechanosensitive channel MscL implicates elements crucial for mechanosensation. Mol. Microbiol. 28, 583-92