Fig. 1. T-Plastin affects the movement of VCA beads in a dose-dependent manner. (A) Time-lapse phase-contrast microscopy of bead movement. Beads were incubated in HeLa-cell extracts in the absence (control, left) or presence (1.1 µM, middle, and 2.2 µM, right) of endogenous T-plastin, observed from 3 minutes to 7 minutes (top to bottom). Little depolymerization of the actin tail is observed when T-plastin is added (black arrow). (B) Bead velocity as a function of T-plastin concentration. Bead velocity shows a bell-shaped dependence on T-plastin concentration with a maximum velocity at 1.1 µM T-plastin. Each bar represents the mean±s.d. of 20 measurements. An asterisk (*) indicates results that differ significantly from the results obtained with the addition of 1.1 µM T-plastin (P<0.0001).