PtdIns-3-P binding protein that tethers the ER to vacuoles at MCSs; coordinates lipid synthesis and storage at the ER-vacuole interface; proposed function in spatial organization of sphingolipid metabolism and adaptive endocytic remodeling of Mup1p; ER anchored, contacting the vacuole surface in trans via the PtdIns-3-P binding Phox (PX) domain; mutation affects nuclear and mitochondrial transmission to buds; similar to 4 human genes including SNX14 which is associated with neurological disease