Mechanosensitive channel of large conductance (MscL) (MscL)

The mechanosensitive channel of large conductance (MscL) in Escherichia coli serves as a critical safety valve that protects the bacterium from lysis during extreme osmotic downshock (UniProt P0A721). It senses increases in membrane tension and responds by opening a large, non-selective pore to allow the rapid efflux of cytoplasmic solutes (PubMed: 15561136). This channel is a homopentameric protein that transitions from a closed to an open state when the lipid bilayer is stretched (PubMed: 10361010). Because MscL is widely conserved across bacterial species but absent in humans, it represents a promising target for novel antibiotic development (PubMed: 28811355). Pharmacological activation of MscL by small-molecule agonists, such as dihydrostreptomycin or synthetic compounds like K05, causes the channel to open at lower-than-normal tensions (PubMed: 25918380). This inappropriate opening leads to the lethal leakage of essential ions and metabolites, effectively killing the bacterium (PubMed: 30104371). This gain-of-function mechanism provides a unique pathway for antimicrobial action that is distinct from traditional antibiotic classes. Research continues to explore MscL as a delivery vehicle for larger therapeutic molecules into the bacterial cytoplasm (PubMed: 21903913).

Other names

Large-conductance mechanosensitive channelmscLMechanosensitive ion channel protein MscL

Agonism or gain-of-function activation leads to uncontrolled leakage of cytoplasmic contents and bacterial cell death.