Small GTPase which cycles between active GTP-bound and inactive GDP-bound states. In its active state, binds to a variety of effector proteins playing a key role in the regulation of endo-lysosomal trafficking. Governs early-to-late endosomal maturation, microtubule minus-end as well as plus-end directed endosomal migration and positioning, and endosome-lysosome transport through different protein-protein interaction cascades (By similarity). Involved in lipophagy, a cytosolic lipase-independent autophagic pathway (By similarity). Plays a role in phagocyte formation and acidification (PubMed:22030555). GTP + H2O = GDP + H(+) + phosphate Expression increases two-fold during phagocytosis (at protein level). Belongs to the small GTPase superfamily. Rab family. Phosphorylation has been demonstrated on peptides which are common to both Rab7a and Rab7b.