Fig. 8: Schematic representation of ATG8 delipidation importance for autophagy in the different eukaryotic kingdoms.

ATG4-dependent delipidation of ATG8 is considered to be generally conserved in plants, animals, and fungi. However, this process is critical for the early steps of autophagosome maturation in yeast cells (phagophore elongation), while in mammalian cells the same delipidation step is critical for the later stage of autophagy (docking of complete autophagosomes to lysosomes). In this study, we show that although ATG8 delipidation occurs in plants, it is dispensable for autophagy. The different roles ATG8-delipidation plays in autophagosome maturation might be representative of autophagy adaptation to the various strategies for the lytic compartment (single large immobile vacuoles in plant and yeast cells vs numerous small motile lysosomes in animal cells), for phagophore assembly sites (single site in yeast vs numerous sites in animal and plant cells), and autophagosome trafficking towards the lytic compartment (autophagosome formation in the proximity to the vacuole in yeast, trafficking of autophagosomes towards immobile vacuole in plants, coordinated trafficking of autophagosomes and lysosomes to their meeting spot in mammalian cells). C cargo, N nucleus, PE phosphatidylethanolamine.