Rap Guanine Nucleotide Exchange Factor 5 (RAPGEF5)

Members of the RAS subfamily of GTPases function in signal transduction as GTP/GDP-regulated switches that cycle between inactive GDP- and active GTP-bound states. Guanine nucleotide exchange factors (GEFs), such as RAPGEF5, serve as RAS activators by promoting acquisition of GTP to maintain the active GTP-bound state and are the key link between cell surface receptors and RAS activation .

The deduced 580-amino acid protein shares 26.4% identity over 235 amino acids with CDC25. Northern blot analysis detected RAPGEF5 expression in brain and testis, with weaker expression in heart, placenta, lung, pancreas and small intestine. No expression was detected in other tissues examined.