Figure 8.

Critical prolines required for effect of hBest1 on Ca_V1.3. A, Alignment (ClustalW) of the C-terminal region of hBest1, mBest1, mBest2, and mBest3. Boxed amino acids represent the critical CT region involved in the regulation of Ca²⁺ channels. Prolines located at 330 and 334 (indicated by arrows) were mutated. B, I–V relationships for recombinant L-type Ca_V1.3 channel (α₁1.3/β_1b/α₂δ) alone (open circles), with wt-hBest1 (filled circles), or P330W/P334W-hBest1 (triangles). C, Averaged Ba²⁺ peak current densities at −10 mV for Ca_V1.3. *p < 0.01 for Ca channel plus hBest1 compared with Ca channel alone by two-way ANOVA. D, I–V relationship for Ca²⁺-activated Cl⁻ currents recorded with the protocol described in Figure 1Aa from cells transfected with wt-hBest1 (open circles) or P330W/P334W-hBest1 (filled circles). E, Lysates from intact, wt-hBest1, or P330W/P334W mutant transfected HEK293 cells were detected with anti-myc antibodies.