Function: Binds differentially to the SH3 domains of certain proteins of signal transduction pathways. This protein binds preferentially to the ABL1 proto-oncogene, SRC and GRB2. Shows GAP activity for Rac-related proteins but not for Rho- or Ras-related proteins. It inhibits PDGF-induced membrane ruffling mediated by Rac. sequence Caution: Translated as Cys. similarity: Contains 1 BAR domain. similarity: Contains 1 Rho-GAP domain.