Figure 4. Slow actin polymerization rate is associated to senescence in a-iPSCs. (A) Basal expression of beta actin in iPSCs, showing defects in cytoskeletal organization of F-actin in aged cells. (B) Representative images of time-lapse experiments performed on y-iPSCs and a-iPSCs, after cytochalasin D treatment and loading with SiR-actin probe, to monitor the actin cytoskeleton functionality.