hSlo1 Y318S functionally coassembles with hβ1. (A) Comparison of mean normalized currents at −200 mV (left) and 200 mV (right) from patches taken from cells transfected with hSlo1 Y318S DNA (blue) and those cotransfected with hSlo1 Y318S and hβ1 DNAs together. The line width indicates SEM. n = 6–18. (B) Ca²⁺ dependence of G-V V_0.5 in wild-type Slo1 alone (WT; black circles), wild-type hSlo1+hβ1 (black diamonds), hSlo1 Y318S alone (blue circles), and hSlo1 Y318S+hβ1 (red diamonds). n = 6–12. The solution with 11 mM EGTA but without any added Ca²⁺ was assumed to have 10 nM of free Ca²⁺.