IMPAIRED MECHANICAL STABILITY, MIGRATION AND CONTRACTILE CAPACITY IN VIMENTIN-DEFICIENT FIBROBLASTS

Loss of a vimentin network due to gene disruption created viable mice that did not differ overtly from wild-type littermates. Here,. primary fibroblasts derived from vimentin-deficient (-/-) and wild-type (+/+) mouse embryos were cultured, and biological functions were studied in in vitro systems resembling stress situations. Stiffness of -/- fibro blasts was reduced by 40% in comparison to wild-type cells. Vimentin-d eficient cells also displayed reduced mechanical stability, motility a nd directional migration towards different chemo-attractive stimuli. R eorganization of collagen fibrils and contraction of collagen lattices were severely impaired. The spatial organization of focal contact pro teins, as well as actin microfilament organization was disturbed. Thus , absence of a vimentin filament network does not impair basic cellula r functions needed for growth in culture, but cells are mechanically l ess stable, and we propose that therefore they are impaired in all fun ctions depending upon mechanical stability.