MKL1 nuclear localization induces activation of SM22 promoter expression. (A) Luciferase activity from SM22 promoter-luc was increased when HEL-iMKL1 cells were treated with TPA (data are derived from 3 independent experiments). This activation was blocked by introduction of a dn-MKL1 construct, but was unaffected by the control plasmid (pcDNA5). (B) Activation of the SM22 promoter by TPA treatment is also inhibited by CCG-1423, a small-molecule inhibitor of MKL1 (data are derived from 3 independent experiments). (C-F) Relative endogenous mRNA levels after the indicated times of TPA administration with or without CCG-1423 treatment for SM22 (C), MYL9 (D), MMP9 (E), and MYH9 (F). Error bars indicate the SEM. Data are derived from 3 independent experiments. (G) CD41 and CD49f (top) or CD49b (bottom) expression on HEL-iMKL1 cells with and without CCG-1423 incubation and subsequent TPA treatment for 24 hours.