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protein kinase C conserved region 1 (C1 domain) found in the RAS guanyl-releasing protein (RASGRP) family The RASGRP family includes RASGRP1-4. They function as cation-, usually calcium-, and diacylglycerol (DAG)-regulated nucleotide exchange factor activating Ras through the exchange of bound GDP for GTP. RASGRP1, also called calcium and DAG-regulated guanine nucleotide exchange factor II (CalDAG-GEFII) or Ras guanyl-releasing protein, activates the Erk/MAP kinase cascade and regulates T-cell/B-cell development, homeostasis and differentiation by coupling T-lymphocyte/B-lymphocyte antigen receptors to Ras. RASGRP1 also regulates NK cell cytotoxicity and ITAM-dependent cytokine production by activation of Ras-mediated ERK and JNK pathways. RASGRP2, also called calcium and DAG-regulated guanine nucleotide exchange factor I (CalDAG-GEFI), Cdc25-like protein (CDC25L), or F25B3.3 kinase-like protein, specifically activates Rap and may also activate other GTPases such as RRAS, RRAS2, NRAS, KRAS but not HRAS. RASGRP2 is involved in aggregation of platelets and adhesion of T-lymphocytes and neutrophils probably through inside-out integrin activation, as well as in the muscarinic acetylcholine receptor M1/CHRM1 signaling pathway. RASGRP3, also called calcium and DAG-regulated guanine nucleotide exchange factor III (CalDAG-GEFIII), or guanine nucleotide exchange factor for Rap1, is a guanine nucleotide-exchange factor activating H-Ras, R-Ras and Ras-associated protein-1/2. It functions as an important mediator of signaling downstream from receptor coupled phosphoinositide turnover in B and T cells. RASGRP4 may function in mast cell differentiation. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites. |
Lu S et al.(2020). "CDD/SPARCLE: the conserved domain database in 2020.",