SHP-2 is required for PECAM-1-mediated attenuation of calcium mobilization in B-cell transfectants.
PECAM-1–expressing (A) wild-type or (B) SHP-2–negative DT40 transfectants were loaded with Fura-2AM and preincubated for 10 minutes at room temperature with murine antichicken BCR together with the indicated concentration of F(ab′)2 fragments of PECAM-1.3 Ab (αPECAM-1 mAb). Cells were washed free of unbound Ab and then added to the warmed (37°C) chamber of an SLM 8100 spectrofluorometer. Calcium mobilization was induced by cross-linking of surface-bound Abs on addition of addition of F(ab′)2 fragments of GAM IgG. The intracellular calcium concentration was assessed every 3 seconds over a period of 120 seconds. Note that PECAM-1 co-ligation with the BCR fails to attenuate calcium mobilization in the absence of SHP-2.
