RAB6A, Member RAS Oncogene Family (RAB6A)

The mammalian RAB proteins show striking similarities to the S. cerevisiae YPT1 and SEC4 proteins, Ras-related GTP-binding proteins involved in the regulation of secretion. The predicted human RAB6 protein contains 208 amino acids. Northern blot analysis revealed that the RAB6 gene was expressed as a 3.6-kb mRNA in a human fibroblast cell line.The deduced 208-amino acid protein encoded by this variant differs at only 3 amino acids compared with the previously reported RAB6A isoform.Reexpression of the RAB6A variant in the resistant cell line restored sensitivity to several anticancer drugs. Flow cytometry experiments showed that sensitivity to doxorubicin was associated with increased drug accumulation in cells expressing the RAB6A variant.