Rab3-interacting molecules (RIMs) are synaptic proteins necessary for neuronal transmission and plasticity. Rim1 and Rim2 proteins are expressed in overlapping but distinct patterns throughout the brain. While the ablation of either gene was not lethal in mice, the deletion of both resulted in postnatal mortality. This lethality is due to a defect in neurotransmitter release, synapses without RIM proteins can still release neurotransmitters but are unable to do so in response to normal Ca2+ triggers. Like Rim1, Rim2 is thought to be an effector protein for Rab3, binding to Rab3 on synaptic vesicles in a GTP-dependent manner.Synonyms: KIAA0751, RAB3IP3, RIM 2, RIM2, Rab-3-interacting molecule 2, Rab-3-interacting protein 3, Regulating synaptic membrane exocytosis protein 2