RASGRP1: Functions as a diacylglycerol (DAG)-regulated nucleotide exchange factor specifically activating Ras through the exchange of bound GDP for GTP. Activates the Erk/MAP kinase cascade. Couples T-lymphocytes and B-lymphocytes antigen receptors to the activation of Ras. Hence, regulates T-cells and B-cells development, homeostasis and differentiation. Functions also in FcERI-evoked degranulation and cytokine secretion by mast cells, regulating allergic responses. May also function in other cell types differentiation. Defects in RASGRP1 may contribute to susceptibility to systemic lupus erythematosus (SLE). SLE is a chronic, inflammatory and often febrile multisystemic disorder of connective tissue. It affects principally the skin, joints, kidneys and serosal membranes. SLE is thought to represent a failure of the regulatory mechanisms of the autoimmune system. Aberrantly spliced isoforms and/or diminished levels of RASGRP1 are found in a cohort of SLE patients raising the possibility that dysregulation of this signaling protein contributes to the development of autoimmunity in a subset of SLE patients. Belongs to the RASGRP family. 5 isoforms of the human protein are produced by alternative splicing.
Protein type: GEFs; GEFs, Ras
Chromosomal Location of Human Ortholog: 15q14
Cellular Component: cytosol; Golgi apparatus; membrane; plasma membrane
Molecular Function: calcium ion binding; diacylglycerol binding; guanyl-nucleotide exchange factor activity; lipid binding; phosphatidylcholine binding; phosphatidylserine binding; protein homodimerization activity; Ras guanyl-nucleotide exchange factor activity; zinc ion binding
Biological Process: MAPKKK cascade; positive regulation of granulocyte macrophage colony-stimulating factor production; positive regulation of GTPase activity; positive regulation of JNK cascade; positive regulation of MAP kinase activity; positive regulation of natural killer cell mediated cytotoxicity; positive regulation of protein amino acid phosphorylation; positive regulation of Ras protein signal transduction; positive regulation of tumor necrosis factor production; protein oligomerization; signal transduction
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