Talin, middle domain. Members of this family adopt a structure consisting of five alpha helices that fold into a bundle. They contain a Vinculin binding site (VBS) composed of a hydrophobic surface spanning five turns of helix four. Activation of the VBS causes subsequent recruitment of Vinculin, which enables maturation of small integrin/talin complexes into more stable adhesions. Formation of the complex between VBS and Vinculin requires prior unfolding of this middle domain: once released from the talin hydrophobic core, the VBS helix is then available to induce the 'bundle conversion' conformational change within the vinculin head domain thereby displacing the intramolecular interaction with the vinculin tail, allowing vinculin to bind actin.
Talin, middle domain. Members of this family adopt a structure consisting of five alpha helices that fold into a bundle. They contain a Vinculin binding site (VBS) composed of a hydrophobic surface spanning five turns of helix four. Activation of the VBS causes subsequent recruitment of Vinculin, which enables maturation of small integrin/talin complexes into more stable adhesions. Formation of the complex between VBS and Vinculin requires prior unfolding of this middle domain: once released from the talin hydrophobic core, the VBS helix is then available to induce the 'bundle conversion' conformational change within the vinculin head domain thereby displacing the intramolecular interaction with the vinculin tail, allowing vinculin to bind actin.