The autophagosomal protein LGG-2 acts synergistically with LGG-1 in dauer formation and longevity in C. elegans

Autophagy has an important function in degrading cytoplasmic components to maintain cellular homeostasis, but is also required during development. The formation of the autophagic vesicles requires the recruitment of the Atg8 ubiquitin-like proteins to the membrane of the nascent autophagosomes. Atg8 is a highly conserved gene which has been duplicated during metazoan evolution. In this report we have investigated, in the nematode C. elegans, the functions and localizations of the two Atg8p homologues LGG-2 and LGG-1. Phylogenetic analyses suggest that LGG-2 is more closely related to the human protein LC3 than LGG-1. LGG-1 but not LGG-2 is able to functionally complement the atg8 mutant yeast. The C-terminal glycine residue of LGG-2 is essential for post-translational modification and localization to the autophagosomes. During C. elegans development the two proteins share a similar expression pattern and localization but LGG-2 is more abundant in the neurons. Using genetic tools to either reduce or increa...