Recombinant PLST-1 binds and bundles F-actin in vitro. (A) High-speed (150,000 g) F-actin cosedimentation assays were performed with recombinant PLST-1 at increasing F-actin concentrations. (B) Low-speed (14,000 g) F-actin cosedimentation assays were performed with recombinant PLST-1, α-actinin as a positive control, and BSA as a negative control. S, supernatant; P, pellet.