May play a role in vesicle-mediated protein trafficking to lysosomal compartments and in membrane docking/fusion reactions of late endosomes/lysosomes. Required for proper trafficking and targeting of the collagen-modifying enzyme lysyl hydroxylase 3 (LH3) to intracellular collagen . Mediates phagolysosomal fusion in macrophages . Proposed to be involved in endosomal maturation implicating VIPAS39. In epithelial cells, the VPS33B:VIPAS39 complex may play a role in the apical recycling pathway and in the maintenance of the apical-basolateral polarity . Seems to be involved in the sorting of specific cargos from the trans-Golgi network to alpha-granule-destined multivesicular bodies (MVBs) promoting MVBs maturation in megakaryocytes (By similarity).
Subcellular locations: Late endosome membrane, Lysosome membrane, Early endosome, Cytoplasmic vesicle, Clathrin-coated vesicle, Recycling endosome
Colocalizes in clusters with VIPAS39 at cytoplasmic organelles (, ). Colocalizes with RAB11A and VIPAS39 on recycling endosomes . Colocalizes with AP-3, clathrin, Rab5 and Rab7b . Colocalizes with M.tuberculosis PtpA in the cytosol of tuberculosis-infected macrophages and associates with phagosomes .
Ubiquitous; highly expressed in testis and low expression in the lung.