Reference: Mizushima N, et al. (1998) A new protein conjugation system in human. The counterpart of the yeast Apg12p conjugation system essential for autophagy. J Biol Chem 273(51):33889-92

Reference Help

Abstract


Autophagy is an intracellular process for bulk degradation of cytoplasmic components. We recently found a protein conjugation system essential for autophagy in the yeast, Saccharomyces cerevisiae. The C-terminal glycine of a novel modifier protein, Apg12p, is conjugated to a lysine residue of Apg5p via an isopeptide bond. This conjugation reaction is mediated by Apg7p, a ubiquitin activating enzyme (E1)-like enzyme, and Apg10p, suggesting that it is a ubiquitination-like system (Mizushima, N., Noda, T., Yoshimori, T., Tanaka, Y., Ishii, T., George, M. D., Klionsky, D. J., Ohsumi, M. , and Ohsumi, Y. (1998) Nature 395, 395-398). Although autophagy is a ubiquitous process in eukaryotic cells, no molecule involved in autophagy has yet been identified in higher eukaryotes. We reasoned that this conjugation system could be conserved. Here we report cloning and characterization of the human homologue of Apg12 (hApg12). It is a 140-amino acid protein and possesses 27% identity and 48% similarity with the yeast Apg12p, but no apparent homology to ubiquitin. Northern blot analysis showed that its expression was ubiquitous in human tissues. We found that it was covalently attached to another protein. This target protein was identified to be the human Apg5 homologue (hApg5). Mutagenic analyses suggested that this conjugation was formed via an isopeptide bond between the C-terminal glycine of hApg12 and Lys-130 of hApg5. These findings indicate that the Apg12 system is well conserved and may function in autophagy also in human cells.

Reference Type
Authors
Mizushima N, Sugita H, Yoshimori T, Ohsumi Y
Primary Lit For
Additional Lit For
Review For

Interaction Annotations


Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.

Interactor Interactor Type Assay Annotation Action Modification Phenotype Source Reference

Gene Ontology Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.

Gene Gene Ontology Term Qualifier Aspect Method Evidence Source Assigned On Annotation Extension Reference

Phenotype Annotations


Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.

Gene Phenotype Experiment Type Mutant Information Strain Background Chemical Details Reference

Regulation Annotations


Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, SPELL, or YeastMine.

Regulator Target Experiment Assay Construct Conditions Strain Background Reference