Rab5b: Proteins and Enzymes

Rab5b is a member of the Rab family of small (monomeric) G proteins. Like other small G proteins, Rab5b switches between an inactive, GDP-form and an active, GTP-bound form. GDP/GTP exchange factors (GEFs) catalyse the conversion from the GDP-bound form to the GTP-bound form, while GTPase-activating proteins (GAPs) catalyse GTP hydrolysis to GDP. 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. Furthermore, Rab5b interacts with LRRK2, the defective gene at the PARK8 locus that results in Parkinson's disease. Roles for Rab5b in neurodegenerative disease, neuroprotection, and synaptic plasticity have been suggested.