protein kinase C conserved region 1 (C1 domain) found in RAS guanyl-releasing protein 2 (RASGRP2) and similar proteins
RASGRP2, also called calcium and DAG-regulated guanine nucleotide exchange factor I (CalDAG-GEFI), Cdc25-like protein (CDC25L), or F25B3.3 kinase-like protein, functions as a calcium- and DAG-regulated nucleotide exchange factor specifically activating Rap through the exchange of bound GDP for GTP. It may also activate other GTPases such as RRAS, RRAS2, NRAS, KRAS but not HRAS. RASGRP2 is also 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. 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.