The small GTPases Rab are key regulators of intracellular membrane trafficking, from the formation of transport vesicles to their fusion with membranes. Rabs cycle between an inactive GDP-bound form and an active GTP-bound form that is able to recruit to membranes different sets of downstream effectors directly responsible for vesicle formation, movement, tethering and fusion. That Rab may be involved in endocytic recycling and may regulate the transport to the plasma membrane of transmembrane proteins. May regulate the assembly and the activity of tight junctions. May play a role in angiogenesis through regulation of endothelial cells chemotaxis. May be involved in neurite outgrowth. Has also been proposed to play a role in post-Golgi membrane trafficking from the TGN to the recycling endosome. Finally, it has been involved in insulin-induced transport to the plasma membrane of glucose transporters. Tight junctions or associated with vesicles scattered throughout the cytoplasm in cells lacking tight junctions (By similarity). Relocalizes to the leading edge of lamellipodia in migrating endothelial cells (By similarity). Belongs to the small GTPase superfamily. Rab family.