Anti-phospho-RasGRP2 (Ser587), pAb (IG-1209)

Affinity purified on the phospho-peptide and depleted several-fold on the dephospho-peptide. RasGRP2 functions as a calcium- and DAG-regulated nucleotide exchange factor specifically activating small GTPases, including Rap1/RAS3, through the exchange of bound GDP for GTP. It may also activate other GTPases such as RRAS, RRAS2, NRAS, KRAS but not HRAS. The protein is expressed in platelets, neutrophils and T lymphocytes. RasGRP2 functions in aggregation of platelets and adhesion of T lymphocytes and neutrophils probably through inside-out integrin activation. S587 was identified as the major PKA phosphorylation. Phosphorylation of S587 correlated with the inhibitory effect of PKA on Rap1b activation in platelets. In vitro, ERK1/2 phosphorylates RasGRP2 at Ser394 to limit its exchange activity and inhibits its ability to activate the small GTPase Rap1 that ultimately leads to decreased activation of ERK1/2 in cells.