LC3 is a mammalian homolog of the yeast protein Atg8, first identified as a light chain of the microtubule-associated proteins MAP1A/B. The only known marker for both the inner and outer autophagosome membrane, at least three mammalian transcript variants are known to exist. Antibody suppliers now offer a wide choice of LC3 antibodies for the identification and tracking of autophagic activity. One of the most commonly used ways to monitor mammalian autophagy is to track the conversion of LC3 by