coq9 encodes the fission yeast Coq9 protein of the COQ9 family, a mitochondrial component of the CoQ biosynthetic complex. By homology with human COQ9 and S. cerevisiae Coq9, it is a membrane-associated lipid-binding protein with a TetR-like fold that binds isoprenoid CoQ intermediates and presents them to the Coq7 hydroxylase. Deletion of coq9 abolishes CoQ10 synthesis and gives the shared coq-mutant phenotypes; unlike the other S. pombe coq mutants, the deletion is not complemented by the human ortholog.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005739 mitochondrion | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | ACCEPT | Summary: ORFeome YFP screen: mitochondrion. Reason: Genome-wide YFP-tagging screen (HDA) placed Coq9 in mitochondria, in agreement with the single-gene Coq9-GFP/MitoTracker result (PMID:24911838). Direct evidence from an assay that cannot resolve the sub-compartment: ACCEPT at the root organelle term. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins, corresponding to approximately 90% of the fission yeast proteome, by tagging each ORF with the yellow fluorescent protein PMID:24911838 These results are consistent with those of a previous study [44] that examined the localization of 4,431 S. pombe proteins |
| GO:0005739 mitochondrion | IDA PMID:24911838 Functional conservation of coenzyme Q biosynthetic genes amo... | ACCEPT | Summary: Mitochondrial localisation of the tagged protein. Reason: Coq9-GFP expressed in the corresponding deletion strain localises to MitoTracker-stained mitochondria (PMID:24911838). Whole-organelle co-staining: ACCEPT at the root organelle term. Supporting Evidence: PMID:24911838 The Dps1, Ppt1/Coq2, Coq3, Coq4, Coq5, Coq6, Coq7, Coq8, and Coq9 GFP fusion proteins also localized to the mitochondria PMID:24911838 The results presented here demonstrate that all of the S. pombe Coq proteins localize to mitochondria, indicating that CoQ biosynthesis occurs in these cellular compartments. |
| GO:0005739 mitochondrion | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt/ARBA location mapping; consistent. Reason: UniProt SubCell mapping (GO_REF:0000044). Mitochondrial location is shown on the target: UniProt curates it with experimental evidence (PMID:16823372), and a Coq9-GFP fusion co-localised with MitoTracker-stained mitochondria (PMID:24911838). Root organelle term kept. Supporting Evidence: file:SCHPO/coq9/coq9-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion {ECO:0000269|PubMed:16823372}. PMID:24911838 The Dps1, Ppt1/Coq2, Coq3, Coq4, Coq5, Coq6, Coq7, Coq8, and Coq9 GFP fusion proteins also localized to the mitochondria |
| GO:0005743 mitochondrial inner membrane | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT inference; consistent. Reason: IBA from PAINT node PTN000484410 (PTHR21427, GO_REF:0000033). S. pombe data resolve only the mitochondrion (GFP and ORFeome localisation). The inner-membrane placement rests on the PAINT node seeded by S. cerevisiae Coq9 and human COQ9 (O75208), whose membrane association UniProt transfers by similarity (ECO:0000250 from O75208/Q05779); accepted as a sound family-level inference. The S. cerevisiae and human COQ9 reviews accept inner-membrane IDA rows for the orthologs. Supporting Evidence: file:SCHPO/coq9/coq9-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion {ECO:0000269|PubMed:16823372}. file:SCHPO/coq9/coq9-uniprot.txt Membrane-associated protein that warps the membrane surface to access and bind aromatic isoprenes with high specificity, including ubiquinone (CoQ) isoprene intermediates and presents them directly to coq7, therefore facilitating the coq7-mediated hydroxylase step. |
| GO:0006744 ubiquinone biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT inference; ubiquinone biosynthesis step. Reason: IBA from PAINT node PTN000484410 (PTHR21427, GO_REF:0000033). Shown on the target: the S. pombe coq9 deletion cannot synthesize CoQ (PMID:24911838). UniProt describes the role in CoQ biosynthesis by similarity to human COQ9 and S. cerevisiae Coq9; the IBA adds that the role is inherited across the COQ9 family. By homology Coq9 contributes the lipid-presenting activity the Coq7 step depends on, so it does part of the work of the process. Supporting Evidence: PMID:24911838 the Δcoq4, Δcoq5, Δcoq6, and Δcoq9 strains are also unable to synthesize CoQ file:SCHPO/coq9/coq9-uniprot.txt Participates in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration. |
| GO:0006744 ubiquinone biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: Mapping; consistent. Reason: ARBA/InterPro/UniPathway mapping (GO_REF:0000120). Same claim as the IMP and IBA rows: the S. pombe coq9 deletion cannot synthesize CoQ (PMID:24911838); UniProt describes the role by similarity to the human and budding-yeast orthologs. Supporting Evidence: PMID:24911838 the Δcoq4, Δcoq5, Δcoq6, and Δcoq9 strains are also unable to synthesize CoQ file:SCHPO/coq9/coq9-uniprot.txt Participates in the biosynthesis of coenzyme Q, also named ubiquinone, an essential lipid-soluble electron transporter for aerobic cellular respiration. |
| GO:0006744 ubiquinone biosynthetic process | IMP PMID:24911838 Functional conservation of coenzyme Q biosynthetic genes amo... | ACCEPT | Summary: Deletion abolishes CoQ10 production (systematic analysis of the S. pombe coq genes). Reason: Deletion of the gene abolishes CoQ10 synthesis and gives the shared coq-mutant phenotypes (PMID:24911838). Coq9 performs a step of the pathway, so it does part of the work; core process. Supporting Evidence: PMID:24911838 Here, we expand these findings by identifying ten genes (dps1, dlp1, ppt1, and coq3-9) that are required for CoQ synthesis. PMID:24911838 Overall, these data indicate that, like the S. pombe Δdps1, Δdlp1, Δppt1/coq2, Δcoq3, Δcoq7, and Δcoq8 strains described previously, the Δcoq4, Δcoq5, Δcoq6, and Δcoq9 strains are also unable to synthesize CoQ. |
| GO:0008289 lipid binding | IBA GO_REF:0000033 | ACCEPT | Summary: Lipid (CoQ-intermediate) binding, as for S. cerevisiae Coq9, which presents intermediates to Coq7. Reason: IBA from PAINT node PTN000484410 (PTHR21427, GO_REF:0000033). Family-level inference: UniProt transfers the isoprene-lipid binding function by similarity from human COQ9 (O75208) and S. cerevisiae Coq9 (Q05779), and S. pombe coq9 carries the COQ9 Pfam domain (PF08511). No lipid-binding assay exists for the S. pombe protein. Human COQ9 binds aromatic isoprene CoQ intermediates directly (PMID:30661980). Core function, matching the human and S. cerevisiae COQ9 reviews and the module annoton; human COQ9 does not complement the S. pombe deletion (PMID:24911838), so lineage-specific partner interfaces may differ. Supporting Evidence: file:SCHPO/coq9/coq9-uniprot.txt Membrane-associated protein that warps the membrane surface to access and bind aromatic isoprenes with high specificity, including ubiquinone (CoQ) isoprene intermediates and presents them directly to coq7, therefore facilitating the coq7-mediated hydroxylase step. file:SCHPO/coq9/coq9-uniprot.txt Pfam; PF08511; COQ9; 1. PMID:30661980 We show that COQ9 repurposes the bacterial TetR fold to bind aromatic isoprenes with high specificity, including CoQ intermediates that likely reside entirely within the bilayer. |
| GO:0008289 lipid binding | IEA GO_REF:0000002 | ACCEPT | Summary: Lipid (CoQ-intermediate) binding, as for S. cerevisiae Coq9, which presents intermediates to Coq7. Reason: InterPro2GO mapping (GO_REF:0000002, IPR012762). Same claim as the IBA row; rests on COQ9 family membership (Pfam PF08511) and on the by-similarity UniProt function transferred from the human and budding-yeast orthologs. No S. pombe binding assay. Human COQ9 binds aromatic isoprene CoQ intermediates directly (PMID:30661980). Core function, matching the human and S. cerevisiae COQ9 reviews and the module annoton; human COQ9 does not complement the S. pombe deletion (PMID:24911838), so lineage-specific partner interfaces may differ. Supporting Evidence: file:SCHPO/coq9/coq9-uniprot.txt Membrane-associated protein that warps the membrane surface to access and bind aromatic isoprenes with high specificity, including ubiquinone (CoQ) isoprene intermediates and presents them directly to coq7, therefore facilitating the coq7-mediated hydroxylase step. file:SCHPO/coq9/coq9-uniprot.txt Pfam; PF08511; COQ9; 1. PMID:30661980 We show that COQ9 repurposes the bacterial TetR fold to bind aromatic isoprenes with high specificity, including CoQ intermediates that likely reside entirely within the bilayer. |
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