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 an inactive GDP-bound form and an active GTP-bound form that is able to recruit to membranes different sets of downstream effectors directly responsible for vesicle formation, movement, tethering and fusion (By similarity). RAB9B is involved in the transport of proteins between the endosomes and the trans Golgi network (By similarity). May use NDE1/NDEL1 as an effector to interact with the dynein motor complex in order to control retrograde trafficking of RAB9-associated late endosomes to the TGN (PubMed:34793709). {ECO:0000250|UniProtKB:P51151, ECO:0000250|UniProtKB:P62820, ECO:0000269|PubMed:34793709}. This is the function of RAB9B (RAB9B, member RAS oncogene family, ENSG00000123570).