Fig. 6. ß1PIX induced the formation of microvillus-like structures by activating Cdc42. (A) The formation of microvillus-like structures was blocked by Cdc42^N17 but not Rac1^N17. Scanning electron micrographs (SEMs) of HeLa cells microinjected with various plasmid DNA. The DNAs were pXJ-GST vector, pXJ-Flag-ß1PIX, pXJ-Flag-ß2PIX, pXJ-HA-CDC42^V12, pXJ-Flag-ß1PIX plus pXJ-Flag-Rac^N17 and pXJ-Flag-ß1PIX plus pXJ-Flag-Cdc42^N17. The apical surface structures induced by ß1PIX are unlike the filopodia induced by Cdc42^V12. (B) PIX mutants did not induce microvillus-like structures. SEMs of HeLa cells microinjected with plasmid constructs of the PIX mutant constructs pXJ-Flag-N80ß1PIX, pXJ-Flag-ß1PIX-DHm and pXJ-Flag-ß1PIX^1-555. (C) The morphological effect of localized activation of Rac1 and Cdc42. Apical protrusions induced by ß1PIX are a combination of microvillus-like structures and lamellipodia (marked by arrowheads), seen here as higher-magnification SEM. Scale bar, 10 µm.