RAPGEF2 is a guanine nucleotide exchange factor (GEF) that activates Rap and Ras family GTPases by exchanging GDP for GTP, functioning as a molecular link between cell surface receptors and intracellular signaling cascades 1. The protein operates through cAMP-dependent mechanisms in neurons and neuroendocrine cells, where it mediates dopamine D1 receptor-induced ERK phosphorylation in corticolimbic and striatal regions 1. RAPGEF2 participates in mechanotransduction by relaying ECM stiffness signals through RAP2 activation to control YAP/TAZ-mediated cellular responses 2. In kidney podocytes, RAPGEF2 forms a complex with MAGI2 to activate Rap1 signaling essential for maintaining glomerular integrity 3. Clinically, RAPGEF2 variants cause neurodevelopmental disorders characterized by developmental delay, epilepsy, and motor dysfunction 4, while repeat expansions in the RAPGEF2 gene cause familial adult myoclonic epilepsy (FAME) 56. In Alzheimer's disease, upregulated RAPGEF2 mediates oligomeric amyloid-β-induced synaptic loss and cognitive dysfunction through Rap2-JNK signaling 7. Additionally, RAPGEF2 degradation regulates epithelial cell migration; loss of this degradation suppresses breast cancer metastasis 8.