RAB21 is a member of a subfamily of small GTP-binding protein genes of the Ras superfamily that plays an important role in intracellular vesicular targeting. In non-polarized Caco-2 cells, RAB21 showed a general endoplasmic reticulum (ER)-like localization, while in polarized cells, RAB21 localized to apical vesicles. RAB21 has been shown to associate with integrin subunits and to be important for receptor entry into cells via RAB5/RAB21 endosomes. The GTPase-activating protein p120RasGAP regulates cell motility by controlling the return of the endocytosed integrins to the plasma membrane by competing with RAB21 for binding to overlapping sites on the Alpha-tail of endocytosed integrin.
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Protein Aliases: GTP-binding protein RAB21; Rab-12; Ras-related protein Rab-21
Gene Aliases: 9630024B22; KIAA0118; RAB21
Molecular Function: small GTPase