Plays a role in the maturation and acidification of phagosomes that engulf pathogens, such as S.aureus and M.tuberculosis. Plays a role in vesicular trafficking. Plays a role in the fusion of phagosomes with lysosomes. Negatively regulates LPS-induced autophagosome formation in macrophages possibly by implicating PI3K (By similarity). May be involved in multiple neurite formation (PubMed:23624502). Interacts with BECN1. Probably associates with the PI3K (PI3KC3/PI3K-III/class III phosphatidylinositol 3-kinase) complex (By similarity). Interacts with UACA. Interacts with isoform a of RASSF1 (PubMed:23294242). Does not interact with isoform c of RASSF1 (PubMed:23294242). Recruited to phagosomes containing S.aureus or Mycobacterium. Belongs to the small GTPase superfamily. Rab family.