Fig. 4.
Requirement of functional DH domain for P-Rex1-dependent reconstitution of superoxide production. (A) Schematic representation of the full-length P-Rex1 and its deletion and point mutants. (B) Absence of fMLF-induced superoxide generation in COSphox cells expressing the E56A/N238A double mutations that disrupt the function of the DH domain. (C) Quantification of data in (B). The inset shows expression of the full-length P-Rex1 and E56A/N238A double mutant in the transfected COSphox cells as determined with Western blotting. (D) the full-length P-Rex1, but not its E56A/N238A double mutant, mediates fMLF-induced Rac1 activation as determined in RBD-GST pull-down assay. Densitometric analysis was performed and relative level of the active Rac1 is shown as fold change compared to the vector-transfected, unstimulated sample, after normalization against the expression level of total Rac1. Data shown are mean±SEM and are representative of three independent experiments. * P<0.05. A color version of panel (B) is available online.