RAP1GAP2 (RAP1 GTPase activating protein 2) is a GTPase-activating protein that terminates RAP1 signaling by converting active GTP-bound RAP1 to its inactive GDP-bound state 1. The protein is expressed in multiple splice variants and exhibits strong GTPase-stimulating activity toward RAP1 in transfected cells 1. RAP1GAP2 plays critical roles in platelet function by regulating integrin activity and hemostasis through interactions with synaptotagmin-like protein 1 (Slp1) and Rab27, forming a trimeric complex that modulates dense granule secretion 2. The protein is subject to complex regulation through phosphorylation by cGMP-dependent protein kinase I and 14-3-3 protein binding, which affects its cellular localization and function during platelet activation and inhibition 31. In neuronal development, RAP1GAP2 regulates axon outgrowth in olfactory sensory neurons, with high expression during early postnatal development that coincides with axon refinement periods 4. Disease associations include sex-specific asthma risk alleles and involvement in aflatoxin B1-induced malignant transformation 56. Additionally, RAP1GAP2 methylation has been associated with central adiposity traits 7, suggesting broader metabolic regulatory roles.