ALPHA(1)-BETA INTERACTION IN VOLTAGE-GATED CARDIAC L-TYPE CALCIUM CHANNELS

The beta subunits of voltage-gated calcium channels normalize current amplitude, kinetics and voltage dependence of these channels by intera cting with the channel's pore forming submit alpha(1), By screening an epitope expression library of alpha(1Ca) fusion proteins, a beta 2a b inding site of 22 amino acids was identified within the I-II cytoplasm ic linker but not on other cytoplasmic sequences of alpha(1Ca). This b inding site overlaps by 14 amino acids with the conserved 18 amino aci d peptide assumed to be essential for alpha(1)-beta interaction, The c ommon 14 amino acid motif of alpha(1Ca) is sufficient to bind beta 2a, and in addition beta 1a, beta 3 and beta 4. (C) 1997 Federation of Eu ropean Biochemical Societies.