Characterization of light-induced furrow formation. Images of anaphase HeLa cells transfected with PR_GEF and Cyk4 siRNA without (A) or with (B) photoactivation. (C) Images of normally dividing HeLa cell expressing PR_GEF just before (t = 0) and during (light) local illumination at the midzone. Comparison of RhoA biosensor (AHDPH-mCherry; D and E), F-actin (mApple-actin; F and G), and myosin (mApple-MLC; H and I) in cells dividing normally and during light-induced furrow formation. (J) Quantification of recruitment of RhoA biosensor, actin, and myosin at endogenous (gray) or light-induced (red) furrows; each dot represents an individual cell and + indicates the mean for that condition. For all photoactivation experiments, cells were locally illuminated for 20 min. Bars, 5 µm.