The dynamic hypoosmotic response of Vibrio cholerae relies on the mechanosensitive channel MscS
Kristen Ramsey1,2, Madolyn Britt1,3, Joseph Maramba1
1Department of Biology, University of Maryland, College Park, MD, USA.
Abstract:
Vibrio cholerae adapts to osmotic down-shifts by releasing metabolites through two mechanosensitive (MS) channels, low-threshold MscS and high-threshold MscL. To investigate each channel's contribution to the osmotic response, we generated ΔmscS, ΔmscL, and double ΔmscL ΔmscS mutants in V. cholerae O395. We characterized their tension-dependent activation in patch-clamp, and the millisecond-scale osmolyte release kinetics using a stopped-flow light scattering technique. We additionally generated numerical models describing osmolyte and water fluxes. We illustrate the sequence of events and define the parameters that characterize discrete phases of the osmotic response. Survival is correlated to the extent of cell swelling, the rate of osmolyte release, and the completeness of post-shock membrane resealing. Not only do the two channels interact functionally, but there is also an up-regulation of MscS in the ΔmscL strain, suggesting transcriptional crosstalk. The data reveal the role of MscS in the termination of the osmotic permeability response in V. cholerae.
More Related Videos
Related Concept Videos
Ion Channels
Ion channels are specialized integral membrane proteins on the plasma membrane that allow...
Channel Rhodopsins
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Mechanically-gated Ion Channels
Mechanisms of Membrane-bending
Membrane bending can happen due to intrinsic changes in lipid composition or extrinsic association with different proteins. The proteins involved...
Cell Motility through Blebbing
Blebbing Through the Matrix
In multicellular...
Voltage-gated Ion Channels
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several...


