VRK1 levels modulate cell spreading and cytoskeletal rearrangement.

(A) To assess the rate of cell spreading, the areas of individual vector control (blue circles) and 3XF-VRK1-overexpressing (green circles) MCF10A cells were measured at 14, 20, and 48h post seeding (n = 60 cells). (B) As for panel A, the areas of individual scrambled shRNA control (blue circle), sh-VRK1-01 (orange circle), and sh-VRK1-02 (light orange circle) MCF10a cells were measured at 14, 20, and 48h post seeding (n = 60 cells). In Figs A and B, bars indicate the median; statistical significance was determined by Mann-Whitney test. (C and D) Stable MCF0a cells co-expressing either GFP-LifeAct and vector control or GFP-LifeAct and 3XF-VRK1, were wounded and monitored for the rearrangement of the cytoskeleton using time-lapse imaging. Representative images of the cytoskeletal organization of cells along the leading edge are shown in C. White triangles indicate lamellipodia and gray arrows indicate filopodia. Scale bar = 100 μm. Quantification of the average number of filopodia per 40X magnification field is shown in D. (Mean and standard error shown; ***p<0.001) (n = 6 images).