RABEP2 is a Rab GTPase-binding effector protein that plays a role in membrane trafficking and in homotypic early endosome fusion. In this capacity it acts within the endosomal system, where Rab GTPase signals are translated into the fusion of early endosomes. It belongs to the rabaptin family, and its name reflects its ability to bind Rab GTPases as an effector.

Beyond endosomes, RABEP2 participates in arteriogenesis by regulating the cell surface expression and endosomal trafficking of vascular endothelial growth factor receptor 2 (VEGFR2). By interacting with SDCCAG8, RABEP2 localises to centrosomes, where it plays a critical role in ciliogenesis. UniProt records the protein in the cytoplasm, early endosome, centrosome and the basal body of the cilium.

The human RABEP2 gene encodes a protein of the rabaptin family, and the mouse and rat both carry a Rabep2 ortholog. NCBI Gene summarises the protein as predicted to enable GTPase activator activity and growth factor activity, and as involved in regulation of cilium assembly, located in the centrosome, ciliary basal body and cytosol. Researchers studying RABEP2 often examine it alongside its relative RABEP1 when investigating Rab effector biology, endosomal sorting and cilium formation.