FIG. 2.

(A) Quantification of EGFP-VP4 FRAP experiments on the actin cytoskeleton. Quantification was obtained from the measurement of fluorescence intensity from fluorescence image data with METAMORPH software. The analyzed data are from experiments similar to the one presented in Fig. 1. Shown is EGPF-VP4 fluorescence recovery in the photobleached region expressed as a percentage compared of the fluorescence before photobleaching. Fluorescence intensities were standardized by comparison to fluorescence intensities from an unphotobleached part of the cell in order to correct the spontaneous photobleaching which occurs even with low-power laser excitation during image acquisition. Displayed are untreated cells (black line), cells treated for 30 min with 20 μM ML-7 (dotted line), and cells treated for 30 min with 1 μM jasplakinolide (discontinuous dotted line). Data are means ± the standard errors of the means from three independent experiments. (B) To monitor the efficiency of ML-7 treatment, Cos-7 cell lysates were analyzed by Western blotting with anti-diphosphorylated myosin light chain (pp-mlc) from Cell Signaling or anti-myosin light chain (mlc) from Sigma Aldrich. Lane C, control cell lysate; lane DPV, lysate from cells treated for 30 min with 10 μM diperoxovanadate (DPV); lane ML-7 DPV, lysate from cells treated for 30 min with 10 μM DPV and 20 μM ML-7. DPV was prepared as described in reference 1.