The function of ENSG00000166128 (RAB8B, RAB8B, member RAS oncogene family) is as follows. 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). RAB8B may be involved in polarized vesicular trafficking and neurotransmitter release (Probable). May participate in cell junction dynamics in Sertoli cells (By similarity). May also participate in the export of a subset of neosynthesized proteins through a Rab8-Rab10-Rab11-dependent endososomal export route (PubMed:32344433). {ECO:0000250|UniProtKB:P61006, ECO:0000250|UniProtKB:P70550, ECO:0000269|PubMed:32344433, ECO:0000305}.