Schematic representation of structure and function of vinculine tail. (a) Vinculin tail domain with its 5 helix pack; Each helix is shown in different color for easy identification. N and C-terminal domains are shown as threads. The residue numbers of each helix are given. (b) Schematic representation of the functional domains of vinculin and some of its ligands. Vinculin is supposed to cycle between active and inactive conformations. Insertion of the hydrophobic hairpin(C-terminal) into the membrane is thought to be the primary step involved in the Vt detachment from its head. (b)(top) Inactive state of the vinculin is shown in box. In this state, vinculin is held in a "closed", auto-inhibited conformation by intra-molecular interactions between the head and tail domains. (b)(bottom) A model of vinculin activation. Conformational changes in the C-terminal tail domain are thought to play a key role in this action, but there are no significant studies so far that provide the active state conformation in living cells. *Inspired from [5, 6]. For more extensive reviews also refer to [3, 28].