This gene encodes a member of the RAB family, which belongs to the small GTPase superfamily. GTPases of the RAB family bind to various effectors to regulate the targeting and fusion of transport carriers to acceptor compartments. This protein is located at the Golgi apparatus, which regulates trafficking in both a retrograde (from early endosomes and Golgi to the endoplasmic reticulum) and an anterograde (from the Golgi to the plasma membrane) directions. Myosin II is an effector of this protein in these processes. This protein is also involved in assembly of human cytomegalovirus (HCMV) by interacting with the cellular protein Bicaudal D1, which interacts with the HCMV virion tegument protein, pp150. Multiple alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Aug 2011].