Fig. 4. Analysis of the cortactin functional domains required for ECM degradation at invadopodia. (A) A375MM cells transfected with mutant forms of cortactin, display a significantly reduced ability to degrade the ECM compared with control cells transfected with cortactin^WT. Data represent the mean ± s.d. of three independent experiments. Statistical significances were evaluated by Student's t-test: wild type vs NTA, W22A and SH3, P<0.006. (B) Transient re-expression of DsRed-tagged mutant and deleted forms of cortactin following knockdown as determined by immunoblotting. A typical experiment is shown. Line indicates endogenous cortactin. (C) Transient re-expression of FLAG-tagged mutant forms of cortactin following knockdown as determined by immunoblotting. A typical experiment is shown.