RAB39B, Member RAS Oncogene Family (RAB39B)

The deduced 213-amino acid protein has a calculated molecular mass of 24 kD. RAB39B contains 4 domains involved in GTP/GDP binding, 5 RabF domains predicted to interact with regulatory proteins, and a C-terminal prenylation motif (xxCxC). Expression of RAB39B in 16 human tissues was below the level of detection by Northern blot analysis, but PCR analysis detected RAB39B in all tissues examined except heart and liver.

The highest expression was in neuronal precursors and neurons in the hippocampus. Studies in mouse cells showed Rab39b localization to the Golgi apparatus and colocalization with markers that cycle from the cell surface to the trans-Golgi network via sorting and recycling endosomes, suggesting a role in vesicular transport.