Background：

Vacuole membrane protein 1 (VMP1)/TMEM49 is a transmembrane protein localized to intracellular vacuoles and was discovered as a protein that promotes vacuole formation in acinar cells associated with acute pancreatitis (1). Over-expression of VMP1 promotes vacuole formation and subsequent cell death (1). Subsequent studies have shown that VMP1 expression is induced by starvation and the mTOR inhibitor， rapamycin， and can trigger autophagy (2). VMP1 is targeted， along with LC3， to autophagosome membranes (2). Knockdown of VMP1 can inhibit autophagosome formation (2). VMP1 interacts with Beclin-1， a key autophagy protein that activates the Class III PI3 kinase Vps34， which is regulated by a large network of associated proteins (3). VMP1 functions in the degradation and clearance of zymogen-containing vacuoles during experimental pancreatitis (4). During this process， VMP1 interacts with the ubiquitin protease USP9X， suggesting a possible functional link between the molecular machinery of autopha