Lymphocyte activation occurs in part through activation of the Ras signaling pathway following lymphocyte receptor stimulation. The RasGRP family of guanine nucleotide exchange factors (GEFs) catalyzes the exchange of GDP for GTP on Ras family small GTPases, promoting their active GTP-bound form. Diacylglycerol (DAG) or phorbol ester binding to RasGRP family members causes their translocation to the cell membrane and stimulates their activity (1,2). While T-Cells express RasGRP1, B-cells express both RasGRP1 and RasGRP3. RasGRP3 is important in linking B-cell receptor (BCR) activation to Ras signaling (3). In response to BCR stimulation, RasGRP3 is phosphorylated at Thr133 by PKC. This phosphorylation event further activates RasGRP3 in response to DAG, which stimulates PKC activity (4,5).
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.