Mechanosensitive channel MscL gating transitions coupling with constriction point shift
Citations Over Time
Abstract
The mechanosensitive channel of large conductance (MscL) acts as an "emergency release valve" that protects bacterial cells from acute hypoosmotic stress, and it serves as a paradigm for studying the mechanism underlying the transduction of mechanical forces. MscL gating is proposed to initiate with an expansion without opening, followed by subsequent pore opening via a number of intermediate substates, and ends in a full opening. However, the details of gating process are still largely unknown. Using in vivo viability assay, single channel patch clamp recording, cysteine cross-linking, and tryptophan fluorescence quenching approach, we identified and characterized MscL mutants with different occupancies of constriction region in the pore domain. The results demonstrated the shifts of constriction point along the gating pathway towards cytoplasic side from residue G26, though G22, to L19 upon gating, indicating the closed-expanded transitions coupling of the expansion of tightly packed hydrophobic constriction region to conduct the initial ion permeation in response to the membrane tension. Furthermore, these transitions were regulated by the hydrophobic and lipidic interaction with the constricting "hot spots". Our data reveal a new resolution of the transitions from the closed to the opening substate of MscL, providing insights into the gating mechanisms of MscL.
Related Papers
- → Global structural changes of an ion channel during its gating are followed by ion mobility mass spectrometry(2014)68 cited
- → An open‐pore structure of the mechanosensitive channel MscL derived by determining transmembrane domain interactions upon gating(2009)30 cited
- → Reprint of: Mechanosensitive ion channels in cell migration(2021)4 cited
- Studies on sensitivity to tension and gating pathway of MscL by molecular dynamic simulation(2013)
- Mechanosensitive Ion Channels in Bacteria: Functional Domains and Mechanisms of Gating(2003)