May mediate microtubule plus end-directed vesicle transport. Can form homodimers. Interacts (via C-terminus) with MAP1LC3B. Interacts with RAB7A; the interaction with RAB7A induces FYCO1 recruitment to late endosomal/lysosomal compartments. Interacts with MAP1LC3B (By similarity). Localizes to the external but not to the internal membrane of autophagosomes, and upon autophagosome/late endosome/lysosome fusion, it stays on the external surface of autolysosomes. Expressed in heart and skeletal muscle. The disease is caused by variants affecting the gene represented in this entry. Pathogenic mutations in FYCO1 can affect intracellular transport of autophagocytic vesicles from the perinuclear area to the periphery, leading to an accumulation of large numbers of vesicles and hence loss of lens transparency (PubMed:21636066). Truncated N-terminus. Truncated N-terminus.