Ras-related protein Rab-5B, also known as RAB5B, is a member of the Rab family of small (monomeric) G proteins. RAB5B is involved in endocytosis and recycling of cell surface molecules. It interacts with RIN2 and RIN3, which regulate its function, possibly by acting as GEFs. Knockdown of RAB5B abolished group I metabotropic glutamate receptor (mGluR)-mediated neuroprotection. Recombinant human RAB5B protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.