Growth cone dynamics and RhoA regulation in CAD neuroblastoma cells. (A) Illustration of growth cone dynamics and RhoA biosensor activity in CAD cells as a timeline showing three distinct phases: protruding (top row), reshaping (middle row), and collapse (bottom row). The last two occur after LPA treatment. Bars, 10 µm. (B) CAD cell with the growth cone (cyan) and cell body (red) identified by ConeTrack at three time points. Yellow curves show the trajectory of growth cone’s centroid. Bars, 20 µm. (C) Distribution of RhoA biosensor activity in growth cones (red) and cell bodies (blue) before (filled circles) and after (empty circles) LPA treatment. (D) Mean intensity of RhoA biosensor activity at cell edge in growth cones (red) or cell bodies (blue) as a function of time. Black dashed line shows the time point when LPA was added. (C and D) Shaded areas show 95% confidence intervals (n = 19 growth cones; n = 15 cell bodies). (E) Distance from current position of growth cone’s centroid to its terminal position, normalized by distance at time of LPA treatment (black dashed line). The onset of growth cone retraction (red dashed line) is delayed with respect to time of LPA treatment. (F) Correlation between time delay in growth cone retraction and growth cone size immediately preceding LPA treatment (n = 14). Red curve shows a fit to the data using the function y = constant/x.