Within a cell, intermediate
filaments interact with other cytoskeletal
components, altogether providing the cell’s mechanical stability.
However, little attention has been drawn to intermediate filaments
close to the plasma membrane. In this cortex configuration, the filaments
are coupled and arranged in parallel to the membrane, and the question
arises of how they react to the mechanical stretching of the membrane.
To address this question, we set out to establish an in vitro system
composed of a polydimethylsiloxane-supported lipid bilayer. With a
uniaxial stretching device, the supported membrane was stretched up
to 34% in the presence of a lipid reservoir that was provided by adding
small unilamellar vesicles in the solution. After vimentin attachment
to the membrane, we observed structural changes of the vimentin filaments
in networks of different densities by fluorescence microscopy and
atomic force microscopy. We found that individual filaments respond
to the membrane stretching with a reorganization along the stretching
direction as well as an intrinsic elongation, while in a dense network,
mainly filament reorganization was observed.