Plays a role in regulating membrane trafficking of cargo proteins. Together with ATP9A and DOP1B, regulates SNX3 retromer-mediated endosomal sorting of WLS away from lysosomal degradation. Homooligomer (PubMed:30213940). Heterotrimer with ATP9A and DOP1B; this interaction is retromer-independent (PubMed:30213940). Interacts with SNX3 (PubMed:30213940). Belongs to the MON2 family. Extended N-terminus.