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. Heterotrimer with ATP9A and DOP1B; this interaction is retromer-independent. Interacts with SNX3. Belongs to the MON2 family.