Membrane-Bound Vimentin Filaments Reorganize and Elongate under Strain

Area of Science:

• Cell biology
• Biophysics
• Materials science

Background:

• Intermediate filaments are crucial for cellular mechanical stability.
• Filaments near the plasma membrane (cortex configuration) are less studied.
• Their response to membrane stretching remains unclear.

Purpose of the Study:

• To investigate the mechanical response of intermediate filaments to plasma membrane stretching.
• To understand the structural reorganization of vimentin filaments under uniaxial strain.

Main Methods:

• Developed an in vitro system with a polydimethylsiloxane-supported lipid bilayer.
• Applied uniaxial stretching to the membrane up to 34%.
• Utilized fluorescence and atomic force microscopy to observe vimentin filament networks.

Main Results:

• Individual vimentin filaments reorganized along the stretching direction and elongated.
• Dense vimentin networks primarily showed reorganization, not significant elongation.
• Filament behavior varied with network density under mechanical stress.

Conclusions:

• Vimentin filaments exhibit distinct mechanical responses based on their density and the applied membrane strain.
• This provides insights into the role of the cell cortex in mechanical resilience.
• The in vitro system effectively models cytoskeletal-membrane interactions under stress.