| Claim/Observation | Experimental system/assay | Key quantitative/statistical result (if present) | Interpretation for Atg5 function/localization | Source (with year, journal, DOI URL) |
|---|---|---|---|---|
| In *Schizosaccharomyces pombe*, Atg5 is a core autophagy factor in the Atg12 conjugation system and acts with Atg12 as the E3 enzyme for Atg8 lipidation. | Review synthesis of fission-yeast autophagy genetics/biochemistry; machinery tables and pathway summary. | No new quantitative value reported in the excerpt. | Supports annotation of Atg5 as a non-enzymatic autophagy factor whose primary biochemical role is to form the Atg12–Atg5 conjugate that enables Atg8-PE formation during autophagosome biogenesis. | Xu & Du 2022, *Cells*, https://doi.org/10.3390/cells11071086 (pqac-00000000, pqac-00000003) |
| Atg16 promotes PAS localization of the Atg12–Atg5 complex, and Atg18a targets the Atg12–Atg5·Atg16 complex to the PAS. | Review synthesis from fission-yeast localization studies. | No new quantitative value reported in the excerpt. | Indicates Atg5 functions at the phagophore assembly site/pre-autophagosomal structure rather than as a diffuse bulk cytosolic enzyme; localization is mediated through the Atg12–Atg5–Atg16 module. | Xu & Du 2022, *Cells*, https://doi.org/10.3390/cells11071086 (pqac-00000000, pqac-00000003) |
| GFP-Atg8 processing and Tdh1-YFP processing are standard assays relevant for testing Atg5-dependent autophagy in fission yeast. | Autophagy flux assays summarized in review. | No specific Atg5 values in the excerpt; assays monitor conversion of GFP-Atg8 to free GFP or Tdh1-YFP to free YFP. | Establishes the main experimental readouts used to infer Atg5 requirement for bulk autophagy/autophagic flux in *S. pombe*. | Xu & Du 2022, *Cells*, https://doi.org/10.3390/cells11071086 (pqac-00000000, pqac-00000003) |
| Canonical conjugation cascade: Atg7 (E1) transfers Atg12 to Atg10 (E2), which conjugates Atg12 to Atg5; the Atg12–Atg5 conjugate then promotes Atg8 conjugation to PE on autophagic membranes. | Biochemical pathway summary in fission-yeast-focused paper on Atg10-like E2. | No Atg5-specific quantitative result in the excerpt. | Defines Atg5’s primary molecular function as the covalent acceptor for Atg12 and part of the E3-like machinery driving Atg8 lipidation, not as a catalyst with independent substrate turnover. | Flanagan et al. 2013, *Cell Cycle*, https://doi.org/10.4161/cc.23055 (pqac-00000002) |
| Yeast Atg12 is covalently linked to Atg5 through Gly186 of Atg12 to Lys149 of Atg5 after transfer through Atg7 and Atg10. | Biochemical/structural analysis of yeast Atg12 and the conjugation cascade. | Specific residues reported: Atg7 Cys507, Atg10 Cys133, Atg12 Gly186, Atg5 Lys149. | Gives residue-level mechanistic support for annotating Atg5 as the acceptor subunit in the ubiquitin-like Atg12 conjugation pathway; strong cross-yeast inference for conserved Atg5-family function. | Popelka et al. 2023, *Int. J. Mol. Sci.*, https://doi.org/10.3390/ijms242015036 (pqac-00000005) |
| The Atg12–Atg5 conjugate binds Atg16 noncovalently to form the Atg12–Atg5–Atg16 complex, which functions as an E3-like ligase for Atg8/LC3 conjugation to PE on the phagophore membrane. | Yeast biochemical/structural work summarized in 2023 study. | No quantitative value in the excerpt. | Supports Atg5 as a scaffold/adaptor in a membrane-associated E3-like complex that enables autophagosome membrane expansion. | Popelka et al. 2023, *Int. J. Mol. Sci.*, https://doi.org/10.3390/ijms242015036 (pqac-00000005) |
| Recent mechanistic model: the ATG12–ATG5–ATG16L1 E3 complex and ATG3 deliver LC3/Atg8 to membranes by a three-step docking sequence involving WIPI2, ATG16L1 helix α2, and a membrane-interacting surface on ATG3. | 2024 mechanistic study combining molecular dynamics, in vitro experiments, and cell-based analyses. | No single summary statistic in the excerpt; study resolved a three-step docking mechanism. | Provides current mechanistic understanding of how the Atg5-containing E3 complex is targeted to PI(3)P-rich phagophore membranes and promotes lipidation efficiency; strong conserved inference for fungal Atg5 function. | Rao et al. 2024, *Science Advances*, https://doi.org/10.1126/sciadv.adj8027 (pqac-00000004) |
| The ATG12–ATG5 unit allosterically activates ATG3 by increasing exposure/reactivity of the ATG3 catalytic thioester carrying Atg8/LC3 for transfer to PE. | 2024 structural/mechanistic lipidation study. | Catalytic residue and thioester intermediate noted in excerpt: ATG3 Cys264 linked to LC3 Gly120. | Refines Atg5 functional annotation: Atg5 is part of an E3-like complex that does not merely recruit substrate but actively promotes efficient Atg8 lipidation through allosteric control of the E2-like enzyme. | Rao et al. 2024, *Science Advances*, https://doi.org/10.1126/sciadv.adj8027 (pqac-00000004) |
| Nucleophagic processing of Pus1-mECitrine to free mECitrine is Atg5-dependent in fission yeast. | Reporter-processing immunoblot assay under DTT treatment and nitrogen starvation. | Processing occurred in WT but was absent in atg5Δ; figures show quantification of free mECitrine levels, though exact numeric values are not provided in the excerpt. | Direct *S. pombe* evidence that Atg5 is required for autophagic/nucleophagic flux. | Zou et al. 2023, *PLOS Biology*, https://doi.org/10.1101/2023.04.24.538066 (pqac-00000012, pqac-00000013) |
| atg5Δ abolishes autophagy-dependent Pus1 and Bqt4 puncta after ER-phagy/nucleophagy induction. | Fluorescence microscopy of induced puncta in WT, atg5Δ, and double mutants. | “No Pus1 or Bqt4 puncta were observed in atg5Δ cells and yep1Δ atg5Δ cells.” | Shows Atg5 is required upstream for formation/enclosure of autophagy-related cargo structures in selective autophagy pathways in *S. pombe*. | Zou et al. 2023, *PLOS Biology*, https://doi.org/10.1101/2023.04.24.538066 (pqac-00000011) |
| Ring-shaped membrane structures that accumulate in yep1Δ cells do not accumulate in the yep1Δ atg5Δ double mutant. | Genetic interaction analysis with fluorescence microscopy. | Qualitative result reported: ring-shaped structures present in yep1Δ but not yep1Δ atg5Δ. | Implies Atg5-dependent core autophagy machinery is necessary for generating the aberrant cargo-associated membrane structures observed when enclosure fails. | Zou et al. 2023, *PLOS Biology*, https://doi.org/10.1101/2023.04.24.538066 (pqac-00000011) |
| In yep1Δ cells, fewer than 10% of nucleus-derived structures co-localize with Atg8, while Pus1 and Bqt4 puncta co-localize strongly with each other. | Colocalization microscopy in selective autophagy context. | <10% co-localization of nucleus-derived structures with Atg8; >80% co-localization of Pus1 and Bqt4. | Although this measures Yep1-pathway defects rather than Atg5 directly, it places the Atg5-dependent machinery in the enclosure step linked to Atg8-decorated autophagic membranes. | Zou et al. 2023, *PLOS Biology*, https://doi.org/10.1101/2023.04.24.538066 (pqac-00000011) |


*Table: This table compiles the key gathered evidence supporting functional annotation of Schizosaccharomyces pombe Atg5 as an Atg12-conjugated, PAS/phagophore-associated E3-like autophagy factor. It integrates direct fission-yeast phenotypes with conserved mechanistic insights from recent structural and biochemical studies.*