RAB31 Human

RAB31, also known as Ras-related protein Rab-31, is a member of the RAS oncogene family. This protein is encoded by the RAB31 gene and plays a crucial role in intracellular membrane trafficking. It is involved in various cellular processes, including protein transport, receptor internalization, and cellular response to insulin stimulus .

The RAB31 gene is located on chromosome 18 and is a protein-coding gene. The protein itself is a small GTPase, which means it can bind and hydrolyze GTP (guanosine triphosphate). RAB31 cycles between an inactive GDP-bound form and an active GTP-bound form. This cycling is essential for its role in membrane trafficking, as the active form recruits downstream effectors responsible for vesicle formation, movement, tethering, and fusion .

RAB31 is required for the integrity and normal function of the Golgi apparatus and the trans-Golgi network. It plays a significant role in the insulin-stimulated translocation of GLUT4 to the cell membrane, which is crucial for glucose uptake in cells. Additionally, RAB31 is involved in the transport of mannose-6-phosphate receptors (M6PR) from the trans-Golgi network to endosomes .

The protein also plays a role in the internalization of the epidermal growth factor receptor (EGFR) from the cell membrane into endosomes. This process is vital for regulating the availability of EGFR on the cell surface and, consequently, the cell’s response to growth signals .

RAB31 has been associated with several diseases, including bladder lateral wall cancer and cardiofaciocutaneous syndrome. Its role in vesicle-mediated transport and the innate immune system highlights its importance in maintaining cellular homeostasis and responding to external stimuli .

Recombinant RAB31 is produced in E. coli as a single, non-glycosylated polypeptide chain containing 232 amino acids. It has a molecular mass of approximately 25.9 kDa and is often fused to a His-tag at the N-terminus for purification purposes. This recombinant protein is used in various research applications to study its function and role in different cellular processes .