The ATG conjugation systems are important for degradation of the inner autophagosomal membrane

Abstract

Open sesame! The autophagosome is a double-membraned intracellular structure involved in the disposal of damaged or defunct organelles. Autophagosome formation requires a number of autophagy-related (ATG) proteins. Among them, the key conjugation systems ATG8 and ATG12 are widely exploited in the detection of autophagy in many organisms. However, their precise function in autophagy remains unknown. Tsuboyama et al. identified an unexpected role of ATG3, an important enzyme in the ATG conjugation systems, in efficient degradation and opening of the inner autophagosomal membrane after fusion with lysosomes (see the Perspective by Levine). Their live-imaging system revealed the entire life of an autophagosome in mammalian cells. Science , this issue p. 1036 ; see also p. 968