RhoA-dependent cortical actin and NMII isoform localization. (A) Representative confocal microscopy images of in vitro cultured control MKs and ERYs and those treated with Y27632. Cells were stained for actin (phalloidin), NMIIA, or NMIIB and their cortical localization was observed. Enlarged views of the areas within the white boxes in each panel are also shown (insets). In 3 independent samples, Y27632 decreased the localization of NMIIB at the cortex in erythroblasts. At least 4 measurements were taken in each cell and at least 17 cells per sample were assessed. (B) A representative image of cortical actin cytoskeleton (phalloidin-stained) in MKs and the fluorescence intensity across the cell obtained by a line scan. The cortical actin intensity is further analyzed to obtain the FWHM, which is indicated by a black line on the fluorescence intensity plot. The corresponding histogram plot represents the FWHM of cortical actin in control and Y27632-treated megakaryocytes and erythroblasts. The data represent the mean ± standard error of the mean of each condition (P < .01). At least 4 measurements were taken in each cell and at least 17 cells per sample per slide were assessed.