1. The VMP1-Beclin 1 interaction regulates autophagy induction
- Author
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Veronica Boggio, Andrea Lo Re, Maria Ines Molejon, Alejandro Ropolo, and Maria I. Vaccaro
- Subjects
Plasma protein binding ,Biology ,BAG3 ,Article ,Cell Line ,Mice ,Autophagy ,Animals ,Humans ,Protein Interaction Domains and Motifs ,ATG16L1 ,PI3K/AKT/mTOR pathway ,Multidisciplinary ,Membrane Proteins ,Class III Phosphatidylinositol 3-Kinases ,Transmembrane protein ,Cell biology ,Membrane protein ,Proto-Oncogene Proteins c-bcl-2 ,Multiprotein Complexes ,Small Ubiquitin-Related Modifier Proteins ,Beclin-1 ,Signal transduction ,Apoptosis Regulatory Proteins ,Protein Binding ,Signal Transduction - Abstract
The Vacuole Membrane Protein 1 -VMP1- is a pancreatitis-associated transmembrane protein whose expression triggers autophagy in several human diseases. In the current study, we unveil the mechanism through which this protein induces autophagosome formation in mammalian cells. We show that VMP1 autophagy-related function requires its 20-aminoacid C-terminus hydrophilic domain (VMP1-AtgD). This is achieved through its direct binding to the BH3 motif of Beclin 1 leading to the formation of a complex with the Class III phosphatidylinositol-3 kinase (PI3K) hVps34, a key positive regulator of autophagy, at the site where autophagosomes are generated. This interaction also concomitantly promotes the dissociation of Bcl-2, an autophagy inhibitor, from Beclin 1. Moreover, we show that the VMP1-Beclin 1-hVps34 complex favors the association of Atg16L1 and LC3 with the autophagosomal membranes. Collectively, these findings reveal that VMP1 expression recruits and activates the Class III PI3K complex at the site of autophagosome formation during mammalian autophagy.
- Published
- 2013