RAB38, Member RAS Oncogene Family (RAB38)

RAB38 has a unique COOH-terminus which would allow posttranslational farnesylation and palmitoylation, lipid modifications normally occurring in RAS proteins but not in other RAB proteins. It is also the only RAB gene showing a predominant mRNA expression in melanocytes, a cell-specific expression pattern likely related to melanosomal transport and docking. Northern blot analysis showed no detectable expression in other normal tissues. Consistent with this lineage specificity, RAB38 mRNA was expressed in 80 to 90% of melanomas (17 of 19), but rarely in nonmelanotic malignancies (1 of 16). RT-PCR and Northern blot analyses showed highest expression of RAB38 in the testis among normal tissues and variable expression in tumor cells, reflecting the proliferative activity in these cells.