Conversion between phosphatidylinositol-3-phosphate and phosphatidylinositol-3,5-bisphosphate on endosomal membranes is critical for maturation of early endosomes to late endosomes/lysosomes, and is regulated by the PIKfyve-Vac14-Fig4 complex. In this study, we screened for the cellular interactome of Vac14 and Fig4 using proximity-dependent biotin labelling (BioID) in 293T cells.