The small GTPases Rab are key regulators of intracellular membrane trafficking, from the formation of transport vesicles to their fusion with membranes. Rabs cycle between active GTP-bound and inactive GDP-bound states. In their active state, drive transport of vesicular carriers from donor organelles to acceptor organelles to regulate the membrane traffic that maintains organelle identity and morphology. Regulates the compacted morphology of the Golgi (Probable). Promotes cytosolic DNA-induced innate immune responses. Regulates IFN responses against DNA viruses by regulating the CGAS-STING signaling axis (By similarity). Together with RAB2A redundantly required for efficient autophagic flux (PubMed:28483915). {ECO:0000250|UniProtKB:P59279, ECO:0000269|PubMed:28483915, ECO:0000305|PubMed:26209634}. This is the function of RAB2B (RAB2B, member RAS oncogene family, ENSG00000129472).