RIMS3 (Rab3-interacting molecule 3) is a member of the RIM protein family, which plays critical roles in regulating synaptic vesicle exocytosis and neurotransmitter release at presynaptic active zones. The RIM family comprises four isoforms (RIMS1-4), with RIMS3 being less characterized compared to RIMS1 and RIMS2. It contains conserved domains, including an N-terminal zinc-finger domain for binding Rab3 GTPases and a C-terminal PDZ domain for interacting with proteins like ELKS/CAST, both essential for synaptic vesicle priming and fusion. RIMS3 is expressed in the central nervous system, particularly in regions like the hippocampus and cortex, but also in peripheral tissues such as pancreatic β-cells and endocrine cells, suggesting roles beyond neurotransmission. Studies link RIMS3 to neurodevelopmental and neuropsychiatric disorders, including schizophrenia and autism spectrum disorders, potentially through its involvement in synaptic plasticity. Antibodies targeting RIMS3 are vital tools for detecting its expression, localization, and interaction partners in research. These antibodies are commonly validated via knockout controls in techniques like Western blotting, immunohistochemistry, or immunofluorescence. Recent work also implicates RIMS3 in glucose homeostasis and diabetes, highlighting its multifaceted biological significance. However, its precise mechanisms and tissue-specific functions remain under investigation, necessitating further studies using well-validated RIMS3 antibodies.