Figure 2.

Actin polymerization induced by JAS treatment. (a and b) FITC-phalloidin labeling of actin bundles attached to the cytoplasmic face of ACPs remaining stuck to coverslips after sonication of the MDCK cells. (a) Control cells have labeling of fine bundles of stress fibers. (b) After JAS treatment, there were thicker more-prominent actin bundles. Bar, 10 μm. (c) Proteins in detergent-soluble and -insoluble fractions of control and JAS-treated MDCK cells were electrophoresed on SDS-PAGE gels and stained with 0.1% Coomassie blue. Left, a 42-kDa band representing actin is present in both the Triton X-100-soluble (lane s) and -insoluble (lane i) fractions of nontreated MDCK cells. Right, the actin band has disappeared from the soluble fraction of JAS-treated cells (lane s) and all of the recovered actin is in the insoluble fraction (lane i), consistent with a conversion to F-actin.