Fig. 3.

Truncation analysis reveals two sites in the KCNQ2 C-terminal domain that are necessary for CaM–KCNQ2 interaction. KCNQ2 C-terminal fragments (shown as boxes with amino acidnumbers) were tested against CaM in the two-hybrid system for LacZ reporter gene expression (positive interactions are indicated by plus signs). Further truncation from either end of Q2CΔ31 (amino acids 321–567) abolished the interaction. The locations of the two putative CaM-binding sites, site 1 (amino acids 321–358; hatched boxes) and site 2 (amino acids 536–567; filled boxes), are indicated in each fragment.