Ras-GRF1 is a guanine nucleotide exchange factor. Its function is to release guanosine diphosphate, GDP, from the signaling protein RAS, thus increasing the activity of RAS by allowing it to bind to guanosine triphosphate, GTP, returning it to its active state. In this way, Ras-GRF1 has a key role in regulating the RAS signaling pathway. Ras-GRF1 knockout mice have been shown to have learning and memory deficits associated with dysregulation of this pathway. Ras-GRF1 has also been shown to be upstream from IGF1, allowing it to control growth in mice. Although it is sometimes known as CDC25, it should not be confused with Cdc25. Ras-GRF1 is a paternally expressed imprinted gene, meaning that only the paternal allele of the gene is translated into protein. Disruption of this epigenetic imprinting also produces learning and memory deficits in neonatal mice.
^Fernandez-Medarde A, Porteros A, De Las Rivas J, Nunez A, Fuster JJ, Santos E (2007). "Laser microdissection and microarray analysis of the hippocampus of Ras-GRF1 knockout mice reveals gene expression changes affecting signal transduction pathways related to memory and learning". Neuroscience146: 272–285. doi:10.1016/j.neuroscience.2007.01.022.
^Drake NM, Park YJ, Shirali AS, Cleland TA, Soloway PD (2009). "Imprint switch mutations at Rasgrf1 support conflict hypothesis of imprinting and define a growth control mechanism upstream of IGF1". Mamm. Genome20 (9-10): 654–63. doi:10.1007/s00335-009-9192-7. PMID19513790.