Rab5 Antibody

Ras-associated protein 5A, also called RAB5, is a protein that in humans is encoded by the RAB5A gene. RAB5 is a rate-limiting component of the machinery regulating the kinetics of membrane traffic in the early endocytic pathway. Tuberin functions as a RAB5GAP in vivo to negatively regulate RAB5-GTP activity in endocytosis. Ectopically expressed ALS2 localized with RAB5 and early endosome antigen-1 onto early endosomal compartments and stimulated the enlargement of endosomes in cultured cortical neurons. The protein is indispensable for a form of receptor tyrosine kinase-induced actin remodeling called circular ruffling. It signals to the actin cytoskeleton through RNTRE, a RAB5-specific GTPase-activating protein (GAP) . RAB5 activity on phagosome membranes began to increase on disassembly of the actin coat encapsulating phagosomes. Activation of the protein was either continuous or repetitive for up to 10 minutes, but it ended before the collapse of engulfed apoptotic cells. Expression of a dominant-negative mutant delayed this collapse of apoptotic thymocytes, showing a role for RAB5 in phagosome maturation.