Autophagy (Greek for “self-eating”) is a process by which cytoplasmic material, including organelles, are targeted to lysosomes for degradation. Autophagy is a dynamic process which involves autophagosome synthesis, delivery of materials to be degraded to the lysosome, and degradation of autophagic substrates inside the lysosome. Historically, methods for studying autophagy focused on counting the number of autophagosomes. This approach, however, has inherent limitations because it turns a dynamic process into a static measurement and it provides limited information about what materials or organelles are being targeted for autophagy. The development of several fluorescent autophagy reporters now allows for the measurement of autophagic flux, or the changes in autophagic activity, and are a more reliable indicator of autophagic activity. The aim of this post is to provide an overview of four autophagy biosensors currently available from Addgene.
