Growing evidence implicates autophagy in cell secretion. Identifying the repertoire of proteins involved with autophagy dependent secretions is key for understanding the underlying mechanism. We use a proximity-dependent biotinylation proteomics strategy to label protein that engage the autophagy regulator MAP1LC3B (LC3/ATG8) in cells; the labeled proteins are then secreted, captured with neutravidin, tryptically digested, and identified by LC-MS/MS. Cells stably expressing BirA* alone serves as control for non-specific cytosolic labeling. SILAC is employed to quantify the degree of LC3B interaction over the background.