Mutations in vimentin disrupt the cytoskeleton in fibroblasts and delay execution of apoptosis

To get new insights into the function of the intermediate filament (IF) protein vimentin in cell physiology, we generated two mutant cDNAs, one with a point mutation in the consensus motif in coillA (R113C) and one with the complete deletion of coil 2B of the rod domain. In keratins and glia filament protein (GFAP). analogous mutations cause keratinopathies and Alexander disease, respectively. Both mutants prevented filament assembly in vitro and inhibited assembly of wild-type vimentin when present in equal amounts. In stably transfected preadipocytes, these mutants caused the complete disruption of the endogenous vimentin network, demonstrating their dominant-negative behaviour. Cytoplasmic vimentin aggregates colocalised with the chaperones alpha B-crystallin and HSP40. Moreover, vimR(113)C mutant cells were more resistant against staurosporine-induced apoptosis compared to controls. We hypothesise that mutations in the vimentin gene, like in most classes of IF genes, may contribute to distinct human diseases. (c) 2005 Elsevier GmbH. All rights reserved.