RAB1B, Member RAS Oncogene Family (RAB1B)

Members of the RAB protein family, such as RAB1B, are low molecular mass monomeric GTPases localized on the cytoplasmic surfaces of distinct membrane-bound organelles. RAB1B functions in the early secretory pathway and is essential for vesicle transport between the endoplasmic reticulum (ER) and Golgi .

The deduced 53-amino acid stretch spans GTP-binding domains II and III and has only 1 or 2 amino acid changes from the homologous stretch in rat Rab1b and human RAB1A, respectively. RAB1B appeared to be a low-abundance transcript in the human melanoma cells.RAB1B contains 4 highly conserved GTPase motifs and a C-terminal geranylgeranylation motif. Northern blot analysis detected strong expression of a major transcript of about 2.4 kb in all tissues examined.