PM blebbing induces MRTF–SRF-mediated up-regulation of Ezrin. (A–C, E, and F) Relative mRNA levels were assessed by quantitative RT-PCR in cells either attached (ctrl.) or plated on poly-HEMA to induce PM blebbing for the indicated periods of time. Results are shown as means from three independent experiments. Error bars indicate SD. Asterisks indicate statistical significance (**, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001). ns indicates no significance (P > 0.05). (A) Relative levels of SRF mRNA were compared in cells treated with either control or siRNA directed against SRF. (B) Relative levels of Ezrin mRNA were compared in cells treated with either control or siRNA directed against SRF. (C) Relative levels of Ezrin mRNA were compared in cells treated with either control or combined siRNAs directed against MRTF-A and MRTF-B. (D) Western blot showing up-regulation of Ezrin upon induced PM blebbing for the indicated periods of time. Tubulin served as a loading control. Relative band intensities ± SD were quantified from two independent experiments. (E and F) Relative levels of Radixin mRNA (E) and Moesin mRNA (F) were compared in cells treated with either control or siRNA directed against SRF. (G) Relative levels of SRF mRNA were assessed by quantitative RT-PCR in cells either attached (ctrl.) or plated on poly-HEMA as indicated. 15 min before and during the time on poly-HEMA, cells were treated with either DMSO, 10 µM ROCK inhibitor Y27632, or 100 µM blebbistatin. Results are shown as means from three independent experiments. Error bars indicate SD. ns indicates no significance (P > 0.05). (H) Relative levels of Ezrin were assessed as in G.