Further characterization of the interaction between the cytoskeletal proteins talin and vinculin

The cytoskeletal protein talin, which is thought to couple integrins to F-actin, contains three binding sites (VBS1-VBS3) for vinculin, a protein implicated in the negative regulation of cell motility and whose activity is modulated by an intramolecular interaction between the vinculin head (Vh) and vinculin tail (Vt) domains.In the present study we show that recombinant talin polypeptides containing the three VBSs (VBS1, residues 498-636 ; VBS2, residues 727-965 ; and VBS3, residues 1943-2157) each bind tightly to the same or overlapping sites within vinculin " -#&) .A short synthetic talin VBS3 peptide (residues 1944-1969) was sufficient to inhibit binding of a "#&I-labelled talin VBS3 polypeptide to vinculin, and NMR spectroscopy confirmed that this peptide forms a 1 : 1 complex in slow exchange with vinculin " -#&). Binding of the "#&I-labelled VBS3 polypeptide was