Abstract
The ubiquitin-like molecule ATG12 is required for the early steps of autophagy. Recently, we identified ATG3, the E2-like enzyme required for LC3 lipidation during autophagy, as an ATG12 conjugation target. Here, we demonstrate that cells lacking ATG12-ATG3 have impaired basal autophagic flux, accumulation of perinuclear late endosomes, and impaired endolysosomal trafficking. Furthermore, we identify an interaction between ATG12-ATG3 and the ESCRT-associated protein Alix (also known as PDCD6IP) and demonstrate that ATG12-ATG3 controls multiple Alix-dependent processes including late endosome distribution, exosome biogenesis and viral budding. Similar to ATG12-ATG3, Alix is functionally required for efficient basal, but not starvation-induced, autophagy. Overall, these results identify a link between the core autophagy and ESCRT machineries and uncover a role for ATG12-ATG3 in late endosome function that is distinct from the canonical role of either ATG in autophagosome formation.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Autophagy / genetics
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Autophagy-Related Protein 12
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Autophagy-Related Proteins
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Calcium Signaling
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Calcium-Binding Proteins / genetics*
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Calcium-Binding Proteins / metabolism
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Endosomes / metabolism*
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Fibroblasts / cytology
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Fibroblasts / metabolism*
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Gene Deletion
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Gene Expression Regulation
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Genes, Reporter
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Green Fluorescent Proteins / genetics
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Green Fluorescent Proteins / metabolism
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Luminescent Proteins / genetics
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Luminescent Proteins / metabolism
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Mice
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Molecular Sequence Data
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Proteins / genetics*
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Proteins / metabolism
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Red Fluorescent Protein
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Ubiquitin-Conjugating Enzymes / deficiency
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Ubiquitin-Conjugating Enzymes / genetics*
Substances
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Atg12 protein, mouse
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Autophagy-Related Protein 12
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Autophagy-Related Proteins
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Calcium-Binding Proteins
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Luminescent Proteins
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Pdcd6ip protein, mouse
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Proteins
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Green Fluorescent Proteins
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Ubiquitin-Conjugating Enzymes
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Atg3 protein, mouse