RASGRP3 and Autoimmunity: In addition, RasGRP1 and RasGRP3 were indicated to regulate the activation of Ras and the ERK1/2-MAP kinase pathway (38), such that RasGRP3 is responsible for the initial level of Ras-GTP expression in the non-stimulated B lymphocytes and its diminished expression leads to deficiency in antibody (Ab) production and hypo-gammaglobulinemia, but reduced expression of RasGRP1 results in autoimmunity and production of antinuclear Abs (ANA) due to defects in the function of T lymphocytes (39).