An Atg4B Mutant Hampers the Lipidation of LC3 Paralogues and Causes Defects in Autophagosome Closure
| Autor: | Hiroko Omori, Naonobu Fujita, Hiromi Fukumoto, Takeshi Noda, Akitsugu Yamamoto, Mitsuko Hayashi-Nishino, Tamotsu Yoshimori |
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| Rok vydání: | 2008 |
| Předmět: |
Autophagosome
Recombinant Fusion Proteins ATG8 Green Fluorescent Proteins ATG5 Mutant Autophagy-Related Proteins Lipid-anchored protein Biology Catalysis Cell Line Mice Phagosomes Autophagy Animals Humans Molecular Biology Phagosome Sequence Homology Amino Acid Phosphatidylethanolamines Cell Membrane Articles Cell Biology Lipid Metabolism Cell biology Cysteine Endopeptidases Biochemistry Mutation embryonic structures Autophagosome membrane Mutant Proteins biological phenomena cell phenomena and immunity Microtubule-Associated Proteins |
| Zdroj: | Molecular Biology of the Cell. 19:4651-4659 |
| ISSN: | 1939-4586 1059-1524 |
| DOI: | 10.1091/mbc.e08-03-0312 |
| Popis: | In the process of autophagy, a ubiquitin-like molecule, LC3/Atg8, is conjugated to phosphatidylethanolamine (PE) and associates with forming autophagosomes. In mammalian cells, the existence of multiple Atg8 homologues (referred to as LC3 paralogues) has hampered genetic analysis of the lipidation of LC3 paralogues. Here, we show that overexpression of an inactive mutant of Atg4B, a protease that processes pro-LC3 paralogues, inhibits autophagic degradation and lipidation of LC3 paralogues. Inhibition was caused by sequestration of free LC3 paralogues in stable complexes with the Atg4B mutant. In mutant overexpressing cells, Atg5- and ULK1-positive intermediate autophagic structures accumulated. The length of these membrane structures was comparable to that in control cells; however, a significant number were not closed. These results show that the lipidation of LC3 paralogues is involved in the completion of autophagosome formation in mammalian cells. This study also provides a powerful tool for a wide variety of studies of autophagy in the future. |
| Databáze: | OpenAIRE |
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