RASGRP1 Gene

RASGRP1 (RAS Guanyl Releasing Protein 1) is a protein-coding gene located on chromosome 15q14. Alternatively spliced transcript variants encoding different isoforms have been identified.

The RASGRP1 gene belongs to a family of genes characterized by the presence of a guanine nucleotide exchange factor (GEF) domain of the Ras superfamily. It functions as a diacylglycerol (DAG)-regulated nucleotide exchange factor that specifically activates Ras by exchanging bound GDP for GTP. It activates the Erk/MAP kinase cascade and regulates T cell and B cell development, homeostasis, and differentiation.

Altered expression of the various isoforms of this protein may be a cause of susceptibility to systemic lupus erythematosus (SLE).

The encoded protein functions as a calcium and diacylglycerol (DAG)-regulated nucleotide exchange factor that specifically activates Ras by exchanging bound GDP for GTP (Roose JP et al. 2005). Activates the Erk/MAP kinase cascade. Regulates T lymphocyte/B lymphocyte development, homeostasis, and differentiation by coupling T lymphocyte/B lymphocyte antigen receptors to Ras (Ebinu JO et al 2000). Regulates NK cell cytotoxicity and ITAM-dependent cytokine production through activation of Ras-mediated ERK and JNK pathways. Acts in mast cell degranulation and cytokine secretion and regulates FcERI-triggered allergic responses. May also play a role in the differentiation of other cell types (Bivona TG et al. 2003).

Diseases associated with RASGRP1 include:

• immunodeficiency 64
• and
• Autoimmune lymphoproliferative syndrome.

1. Bivona TG et al. (2003) Phospholipase Cgamma activates Ras on the Golgi apparatus by means of RasGRP1. Nature 424(6949):694-698.
2. Ebinu JO et al (2000) RasGRP links T-cell receptor signaling to Ras. Blood 95:3199-3203.
3. Mao H et al (2018) RASGRP1 mutation in autoimmune lymphoproliferative syndrome-like disease. J. Allergy Clin. Immun. 142: 595-604.
4. Platt CD et al. (2017) Combined immunodeficiency with EBV positive B cell lymphoma and epidermodysplasia verruciformis due to a novel homozygous mutation in RASGRP1. (Letter) Clin Immun 183: 142-144.
5. Roose JP et al (2005) A diacylglycerol-protein kinase C-RasGRP1 pathway directs Ras activation upon antigen receptor stimulation of T cells. Mol Cell Biol 25:4426-4441