RasGRP1 and RasGRP3 translocate to the plasma membrane where they bind diacylglycerol (Lorenzo et al. 2001) and are phosphorylated (Teixeira et al. 2003, Zheng et al. 2005). Though RasGRP3 is phosphorylated in vitro and in some cell lines (e.g. Ramos cells) by protein kinase C theta (PKC-theta, Zheng et al. 2005), normal B cells do not contain PKC-theta (Meller et al. 1999). Both Rasgrp1 and Rasgrp3 participate in activating Ras in response to BCR signaling in mouse B cells (Coughlin et al. 2005).