Components of P/Q type VGCC. The properties of the voltage gated Ca2+ channels are dependant on the pore forming alpha 1 subunit. The alpha 1 subunit in the case of a P/Q channel is alpha 2.1 which can associate with any of the four beta subunit but in vivo has been shown to predominantly associate with a beta 4 subunit. Alpa 2.1 is shown to specifically interact with Gamma 2 or Gamma 3 subunits of the 10 different gamma subunits known. Of the four Alpha 2 delta subunits know (alpha 2 delta 1-4) the alpha 2 delta 4 subunit is not expressed in the brain. Although, alpha 2 delta subunits are part of the Ca2+ channels complex, the specificty of the alpha 2 delta to a particular alpha 1 subunit has not been identified. Therefore, it is possible that alpha 2.1 may associate with one or more of the alpha 2 delta subunits and only one of them is shown as a part of the Ca2+ channel complex.