Fig. 4.
Activation of Rac-1 induced by cross-linking of the BCR.
Splenocytes from BDF1 mice were stimulated with LPS (15 μg/mL) for 72 hours to generate B lymphoblasts. B lymphoblasts were stimulated with F(ab′)2 fragments of antimouse IgM (40 μg/mL) for the indicated length of time or treated with PBS for 5 minutes (con). Following stimulation, lysates were assayed for GTP-bound endogenous Rac-1 (Rac-1 GTP) as specified earlier. Immunoblots were performed using a Rac-1 monoclonal antibody. One half of the total GTP-bound Rac-1 precipitated was run and the WCL corresponded to 1.4% of the total Rac-1 available for precipitation.
