FIG. 4.

CrkL-deficient cells display haptotaxis defects. (A) Immunoblot analysis for CrkL and Crk-II in MEFs used for panel B. (B) Modified Boyden chamber migration assays. Haptotaxis toward fibronectin was determined as shown in Fig. 3C. Chemotaxis toward serum was determined in an assay similar to the haptotaxis assay except that both sides of the insert were coated with fibronectin with or without fetal bovine serum (10%) (FBS + or −, respectively) included in the lower chamber. Error bars indicate the standard deviation of the sample data obtained in four independent microscopic fields under a 40× objective lens. Three independent experiments yielded similar results.