Figure 2

SM22α depletion alters stress fibre organization. Examples of the 'normal' 'orthogonal' and 'absent' stress fibre phenotypes in response to depletion of SM22 in REF52 cells. dsRed marks the cells expressing the RNAi, and actin stress fibres are visualized with FITC phalloidin, insets represent examples of the actin phenotypes described (A). Quantification of the stress fibre phenotype shows that depletion of SM22α in two independent cell lines leads to a reduction in normal stress fibres and an increase in the cells falling into the 'orthogonal' or 'absent' categories compared to cells expressing a scrambled RNAi sequence (B). C, quantification of the extent of SM22α depletion by ratio to tubulin content by western blotting in REF52 cells as a % of a mock transfected control (dsRed empty vector). The scrambled RNAi did not deplete SM22α compared to control whereas two independent dsRed SM22α RNAi lines of cells, knockdown A and knockdown B, showed a significant reduction of SM22α levels to 40 and 30% respectively. Mean ± SEM of 3 independent experiments; * p < 0.05 as compared to scrambled control in all cases in B and C.