Fig.·2. PMA (PKC activator phorbol myristate acetate) stimulates the recruitment of N-WASP to vesicles associated with actin comet tails. Cell-free vesicle motility assays containing Xenopus cytosol, membranes and 1 ·µmol·l^-1 PMA were fixed in perfusion chambers and immunolabeled with affinity-purified anti-N-WASP antibodies followed by Texas Red-labeled secondary antibodies and FITC–phalloidin. N-WASP and F-actin recruitment occurred in the presence of 75·µmol·l^-1 latrunculin A (Lat A), but comet tails were not observed. ToxB treatment prevented both N-WASP and F-actin recruitment, although nonspecific labeling of fixed membranes could be observed with long exposure times. Bar, 5·µm. Reproduced from Taunton et al. (2000), with permission from the Rockefeller University Press.