The methods described are designed to enable the assignment of an intracellular localization of secretory proteins, either soluble or membrane associated, to later secretory compartments, such as the trans-Golgi network (TGN) or endosome. These two subcellular compartments are closely linked through extensive protein trafficking, in both an anterograde and a retrograde direction. These compartments are likely to be important in the formation of autophagosomes during the process of autophagy. Our current knowledge of how autophagosomes form is scarce, and further investigation into the role that other subcellular compartments have in this process is needed.