The object of this project is to investigate the proximal proteome of ULK1 during mitophagy and the effects of a FIP200 knock down using the APEX2-mediated proximity labeling system. APEX2-ULK1 or APEX2 was fused to 2xFKBP-myc and stably expressed in a cell line stably expressing a truncated FIS1-FRB fusion protein. Treatment with rapalog induces the stable interaction between FRB and FKBP, resulting in tethering of FKBPx2-myc-APEX2-ULK1 or FKBPx2-myc-APEX2 to the outer mitochondrial membrane.