Vimentin is a member of the intermediate filament family of proteins. Intermediate filaments are an important structural feature of eukaryotic cells. They, along with microtubules and actin microfilaments, make up the cytoskeleton. Although most intermediate filaments are stable structures, in fibroblasts, vimentin exists as a dynamic structure.
A vimentin monomer, like all other intermediate filaments, has a central α-helical domain, capped on each end by non-helical amino (head) and carboxy (tail) end domains. Two monomers will twist around each other to form a coiled-coil dimer. Two dimers then form a tetramer, which, in turn, form a sheet by interacting with other tetramers.