Figure 2.

TREM-2–DAP12-mediated phagocytosis requires tyrosine phosphorylation and src kinase activity, and it is enhanced by Syk. (A) T2D12 cells were treated with genistein (tyrosine kinase inhibitor), PP2 (src kinase inhibitor), or ML-7 (myosin light chain kinase inhibitor) for 2 h at the indicated concentrations before addition of 594–E. coli. Controls for binding were treated with cyto D. Bacteria association was assessed by flow cytometry as in Fig 1. To quantify uptake, values obtained with cyto D were subtracted from that of untreated samples. The graph shows values normalized to controls (no inhibitor). *, P ≤ 0.05; **, P < 0.01; ***, P < 0.001 relative to controls. (B) CHO cells were transfected with T1D12, T2D12, D12, or a variant of T2D12 with a mutated ITAM (T2D12ΔITAM). Where indicated, cells were cotransfected with Syk. (C) 594–E. coli association with transfected cells was quantified as in Fig. 1 F. *, P ≤ 0.05; **, P < 0.01; ***, P < 0.001 relative to parental values. (D) T2D12 cells treated with the indicated concentrations of piceatannol were challenged with E. coli, and uptake was analyzed as in Fig. 2 A. **, P < 0.01. The graphs represent the mean of three experiments ± SEM.