Figure 2.
BCR-stimulated Ras activation in Ramos B cells is associated with a shift in the electrophoretic mobility of RasGRP3. (A) Homogenates of Ramos B cells from untreated cells or from cells stimulated with 100 nM PMA for 10 minutes were separated into particulate (Pellet) and soluble (Sup) fractions and assayed for RasGRP3 by immunoblotting. (B) Ramos B cells were stimulated with anti-IgM for various times, and aliquots were assayed for RasGRP3, phospho Erk1/2, Ras-GTP, and total Ras. (C) Total splenocytes isolated from C57BL/6J mice were stimulated with PMA, anti-IgM, anti-kappa, or anti-CD40 for 10 minutes and then assayed for RasGRP3 by immunoblotting. — indicates untreated control.