Autophagy is the crucial waste cleaning system for the cell. Removal of damage organelles, protein aggregates and invading pathogens relies on autophagy ("self-eating" in Greek). Autophagy is also important for organelle biogenesis and stress response. Dysfunction of autophagy has been implicated in a broad spectrum of human diseases, including cancers, neurodegenerative diseases, infectious diseases and metabolic diseases. During autophagy, a double membrane vesicle termed autophagosome is formed with engulfed cellular cargoes and then fused with lysosomes for degradation. We are specifically interested in dissecting the biochemical mechanisms in this process including lipid modification, membrane deformation, membrane curvature sensing, cargo recruitment, and membrane tethering/fusion. Understanding the key regulatory steps in this pathway will allow us to develop new therapeutic tools for human diseases.