Sequence comparison of the GPV cytoplasmic tail and the IQ motif.

(A) Alignment of the cytoplasmic sequence of GPV, K529–G544,18 with the conserved IQ motif of the L-type ion channel subunit α1c,21RC3/neurogranin,30,31 and GAP-43.32,33 The solid lines above the α1c sequence indicate residues that form the IQ motif. The lower line indicates residues minimally required for calmodulin binding by RC3 (solid line), while additional upstream residues involved in the Ca⁺⁺-sensitive interaction include those indicated by the dashed line.32 (B) Helical wheel representation of the GPV sequence (K529–G544) compared with the sequence of α1c.