Cyclodextrins for structural and functional studies of mechanosensitive channels

Area of Science:

• Biophysics
• Molecular Biology
• Membrane Protein Research

Background:

• Mechanosensitive (MS) channels open in response to membrane pressure changes, operating via the 'force-from-lipids' (FFL) principle.
• Studying MS channels in open states traditionally required mutants, limiting research.
• Existing methods for channel activation, like patch-clamp electrophysiology, have limitations.

Purpose of the Study:

• To introduce cyclodextrins (CDs) as a novel tool for generating membrane tension.
• To enable structural and functional studies of MS channels in activated states.
• To validate CDs as a method for activating FFL-principle MS channels.

Main Methods:

• Incubation of proteoliposomes and membrane patches with cyclodextrins (CDs) to induce membrane tension.
• Single-particle cryo-electron microscopy of MS channels in nanodiscs after CD treatment.
• Patch-clamp electrophysiology to record CD-induced channel activity.

Main Results:

• CDs effectively remove lipids from membranes, increasing membrane tension.
• CD-mediated tension activates MS channels, including MscL, which opens near membrane rupture.
• This approach facilitates structural and functional characterization of FFL MS channels.

Conclusions:

• Cyclodextrins provide a versatile and convenient method for activating FFL-principle MS channels.
• CDs enable the study of MS channel structures and functions in tensioned membranes.
• This technique advances research into mechanosensation mechanisms.