Figure 4. Neither TM1 or TM2 from BK β1 is sufficient to confer the characteristic phenotype of β1-containing to BK channel complexes.

(A) Cartoons depicting chimeric constructs that result from swapping individual transmembrane domains (either TM1 or TM2) between hβ1 and hβ4. Regions from β1 and β4 are given in black and grey, respectively. (B) Macroscopic current recordings obtained from I/O oocyte membrane patches expressing cbv1+β4TM1₁ (construct 6) or cbv1+β4TM2₁ (construct 7); Ca²⁺ _i = 10 µM. (C) Averaged G/G_max-V plots of cbv1, cbv1+hβ1, cbv1+hβ4, cbv1+β4TM1₁ and cbv1+β4TM2₁; Ca²⁺ _i = 10 µM. Averaged V_half (D), activation (E) and deactivation (F) time constants (τ_act, τ_deact, respectively) obtained cbv1, cbv1+hβ1, cbv1+hβ4, cbv1+β4TM1₁ and cbv1+β4TM2₁; Ca²⁺ _i = 10 µM. *Different from cbv1 (P<0.05); ^#Different from cbv1+β1 (P<0.05). Error bars correspond to SEM; each point represents the average of ≥4 patches.