Plays a role in apical endocytosis/recycling. Plays a role in the maturation and acidification of phagosomes that engulf pathogens, such as S.aureus and Mycobacterium. Plays a role in the fusion of phagosomes with lysosomes (By similarity). Recruited to phagosomes containing S.aureus or Mycobacterium (By similarity). Highly enriched on apical endocytic structures in polarized epithelial cells of kidney proximal tubules (PubMed:7706395). Present in a variety of tissues, but not in brain. Belongs to the small GTPase superfamily. Rab family.