Characterization of the actin binding properties of the vasodilator-stimulated phosphoprotein VASP

The vasodilator-stimulated phosphoprotein (VASP) colocalizes with the ends of stress fibers in cell-matrix and cell-cell contacts. We report here that bacterially expressed murine VASP directly interacts with skeletal muscle actin in several test systems including cosedimentation, viscometry and pol ymerization assays. It nucleates actin polymerization and tightly bundles a ctin filaments. The interaction with actin is salt-sensitive, indicating th at the complex formation is primarily based on electrostatic interactions. Actin binding is confined to the C-terminal domain of VASP (EVH2). This dom ain, when expressed as a fusion protein with EGFP, associates with stress f ibers in transiently transfected cells. (C) 1999 Federation of European Bio chemical Societies.