PTEN control of ITAM signaling.

(A) Phagocytosis of IgG-sensitized sRBCs by COS7 cells transfected with FcγRIIA receptor, Syk, PTEN, or a mutant (C124S) of PTEN. Phagocytosis of IgG-coated sRBCs by COS7 cells was quantified as described in “Study design.” Bars represent standard deviation of mean. (B) Western blot analysis for PTEN, AKT, and phospho-AKT in COS7 cells after transfection prior to sRBC stimulation. (C) Phagocytic index in COS7 cells transfected with equal amounts of FcγRIIA and EGFP-Syk and different amounts of wildtype PTEN plasmid DNA. (D) Rosette formation in COS7 cells transfected with different amounts of PTEN complementary DNA (cDNA). (E) Western blot analysis for PTEN expression in COS7 cells from panels C and D. (F) Flow cytometric analysis to determine levels of FcγRIIA and EGFP-Syk kinase expression in different transfected populations of COS7 cells shown in Figure 1A.