[Bacterial ion canals]

After an overview of potassium and chloride ion channels found in bacterial inner membrane this review focuses on mechanosensitive ion channels from the inner membrane of Escherichia coli. Mechanosensitive channels, MscL and MscS, have major roles in managing the transition from high to low environments. Biochemical and genetic studies of MscL, combined with structural information derived from X-ray crystalography, have brought the knowledge of how a mechanosensitive channel senses membrane tension. Physiological studies on MscL and on MscS have demonstrated how the mechanosensitive channels contribute to the bacterial membrane response upon hypo-osmotic stress.