A, representative blots showing effects of acute BK treatment (1 μm, 30 s) with or without TGF‐β pre‐treatment (10 ng ml−1, 24 h) in hASMCs transfected with either ARHGEF1 siRNA, or a scrambled siRNA control, on phospho‐MLC20 (Ser19), total MLC20 or GAPDH as a loading control. B, data expressed as total/GAPDH show enhancement of MLC20 protein expression by TGF‐β pre‐treatment (##
P < 0.01 vs. –TGF‐β), and partial suppression of this response by ARHGEF1 siRNA ($$
P < 0.01 vs. scrambled siRNA). Data expressed as phospho/total (C) or phospho/GAPDH (D) show significant enhancement by both BK (*
P < 0.05, **
P < 0.01 vs. control), effects of TGF‐β pre‐treatment (#
P < 0.05, ##
P < 0.01 vs. –TGF‐β) and suppression by ARHGEF1 siRNA ($
P < 0.05, $$
P < 0.01 vs. scrambled siRNA). n = 9 for all data. All comparisons by three‐way ANOVA.