Site specificity in vimentin-membrane interactions: intermediate filament subunits associate with the plasma membrane via their head domains.

Abstract

Fragments of vimentin, generated by chemical or enzymatic cleavages, were analyzed for their capacity to bind to human inverted erythrocyte membrane vesicles. Only peptides comprising the amino-terminal head domain of vimentin molecules were competent in associating with the membranes. In vitro studies also demonstrated that isolated ankyrin (the major vimentin acceptor site on the membrane) binds to an oligomeric species of vimentin and prevents the formation of characteristic 10-nm filaments. These data, taken together with the observation that the NH2-terminal end of vimentin is implicated in the polymerization process, imply that intermediate filaments may contact the membrane in an end-on fashion, using the exposed head domains of their terminal subunits.