act in ▁to ▁the ▁memb rane . ▁ ▁Disc over ed ▁independently ▁by ▁Ben ny ▁Ge iger ▁and ▁Keith ▁B urr idge , ▁its ▁sequence ▁is ▁ 2 0 % - 3 0 % ▁similar ▁to ▁α - c aten in , ▁which ▁serves ▁a ▁similar ▁function . ▁ ▁Binding ▁altern ately ▁to ▁tal in ▁or ▁α - act in in , ▁vin cul in ' s ▁shape ▁and , ▁as ▁a ▁consequence , ▁its ▁binding ▁properties ▁are ▁changed . ▁The ▁vin cul in ▁gene ▁occurs ▁as ▁a ▁single ▁copy ▁and ▁what ▁appears ▁to ▁be ▁no ▁close ▁relative ▁to ▁take ▁over ▁functions ▁in ▁its ▁absence . ▁Its ▁sp lice ▁variant ▁met av in cul in ▁( see ▁below ) ▁also ▁needs ▁vin cul in ▁to ▁heter od imer ize ▁and ▁work ▁in ▁a ▁dependent ▁fashion . ▁ ▁Str ucture ▁▁▁ ▁Vin cul in ▁is ▁a ▁ 1 1 7 - k Da ▁c yt os ke let al ▁protein ▁with ▁ 1 0 6 6 ▁am ino ▁ac ids . ▁The ▁protein ▁contains ▁an ▁acid ic ▁N - term inal ▁domain ▁and ▁a ▁basic ▁C - term inal ▁domain ▁separated ▁by ▁a ▁pro line - rich ▁middle ▁segment . ▁Vin cul in ▁consists ▁of ▁a ▁glob ular ▁head ▁domain ▁that ▁contains ▁binding ▁sites ▁for ▁tal in ▁and ▁α - act in in ▁as ▁well ▁as ▁a ▁ty ros ine ▁ph osph ory lation ▁site , ▁while ▁the ▁tail ▁region ▁contains ▁binding ▁sites ▁for ▁F - act in , ▁p ax ill in ,