FIGURE 4.

Effects of the Arp2/3 inhibitors CK548 and CK636 on actin polymerization in vitro and on T cell chemotaxis. A–D, in vitro effects of CK548 and CK636 on actin polymerization in an in vitro WCA-bead actin polymerization assay as illustrated in D. DMSO, 50 μm CK548, or CK636, along with 8.5 mm actin (10% labeled), 9 mm profilin, 100 nm Arp2/3, and 200 nm capping protein were added for the assay. CT, actin comet tail. E, quantification of TIRF images from the polymerization assay. F, Jurkat T cells were assayed in SDF-1-induced chemotaxis in transwell plates after a 2-h treatment with DMSO, 50 μm CK548, or 50 μm CK636.