(A) Comparison of the basic patch of human Abba with that of MIM. The Lys residues in Abba that had been mutated to Glu are bolded. (B) Cells were transiently co-transfected with constructs as indicated. After 24 h of transfection, cells were analyzed for Rac1 binding as described above. The same membrane was also re-blotted with Myc antibody for equal immunoprecipitation. Also, aliquots of the lysates were immunoblotted with GFP antibody to determine expression of GFP-tagged proteins. (C) Cells were transiently transfected with GFP-Abba and GFP-AbbaK/D, respectively. The level of GTP-Rac in the transfected cells was analyzed as described in the legend of Fig. 3. (D) GFP-AbbaK/D cells (a–d) and GFP-Abba cells (e–h) were plated on fibronectin-coated coverslips and arrested in 0.2% serum-containing medium for 24 h. The arrested cells were treated without (a, b, e and f) or with PDGF (c, d, g and h) for 10 min, and co-stained with GFP antibody (a, c, e and g) and phalloidin (b, d, f and h). Bar: 10 μm.