Vinculin is autoinhibited by the head/tail interaction of the protein. This inhibition can
be released by several ligands, such as PIP2 and talin. VBS is a peptide which
derives from the C-terminal talin sequence and was shown to release the head/tail
interaction of vinculin by binding to the vinculin head (Vh). The vinculin molecule
opens and exposes e.g. ligand binding sites in the vinculin tail (Vt) region.
PIP2 and actin binding have been shown to be mutually exclusive (Steimle et al.,
1999), while binding of VBS opens the vinculin molecule without impairing actin
binding (Bass et al., 2002). The activation of vinculin by talin to connect the actin
cytoskeleton to the plasma membrane is thought to be one of the key mechanisms
for focal adhesion assembly.
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