ppt1 (coq2) encodes the fission yeast 4-hydroxybenzoate polyprenyltransferase (EC 2.5.1.39), a UbiA-family multi-pass membrane enzyme of the mitochondrial inner membrane. It condenses 4-hydroxybenzoate with all-trans-decaprenyl diphosphate, forming the first membrane-bound intermediate of coenzyme Q10 biosynthesis. ppt1 disruption abolishes CoQ10, causing antioxidant dependence on minimal medium, hydrogen peroxide and copper sensitivity and hydrogen sulfide overproduction; S. cerevisiae COQ2 and human COQ2 complement the defect, and overexpression of ppt1 raises CoQ10 content.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004659 prenyltransferase activity | IEA GO_REF:0000002 | MODIFY | Summary: Generic InterPro-derived parent of the specific activity, which is already annotated. Reason: InterPro2GO mapping (GO_REF:0000002, IPR006370). Prenyltransferase activity is correct but general; the specific activity, 4-hydroxybenzoate polyprenyltransferase (EC 2.5.1.39), is supported for S. pombe Ppt1 by UniProt's curated function and catalytic activity (ECO:0000269 PubMed:11092853, with HAMAP MF_03189) and by membership of the UbiA prenyltransferase family (Pfam PF01040). The gene already carries GO:0008412 with experimental support. Same MODIFY as the S. cerevisiae and human COQ2 reviews. Proposed replacements: 4-hydroxybenzoate polyprenyltransferase activity Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Reaction=an all-trans-polyprenyl diphosphate + 4-hydroxybenzoate = a 4-hydroxy-3-(all-trans-polyprenyl)benzoate + diphosphate; file:SCHPO/ppt1/ppt1-uniprot.txt Pfam; PF01040; UbiA; 1. |
| 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 ppt1 in mitochondria, in agreement with the single-gene Ppt1-GFP results (PMID:11092853, PMID:24911838). Direct evidence 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: Ppt1-GFP expressed in the ppt1 deletion co-localises with MitoTracker-stained mitochondria (PMID:24911838), repeating the earlier result (PMID:11092853). ACCEPT at the root organelle term; the inner-membrane rows add the sub-compartment. 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:11092853 Ppt1-green fluorescent protein fusion proteins localized to the mitochondria, indicating that ubiquinone biosynthesis occurs in the mitochondria in S. pombe. |
| GO:0005739 mitochondrion | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt SubCell mapping of the curated mitochondrion location, which rests on Ppt1-GFP localisation in S. pombe; consistent. Reason: UniProt SubCell mapping (GO_REF:0000044). Root organelle term; the UniProt location is experimental (PMID:24911838) and agrees with the earlier Ppt1-GFP result (PMID:11092853). Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion {ECO:0000269|PubMed:24911838}. PMID:24911838 The Dps1, Ppt1/Coq2, Coq3, Coq4, Coq5, Coq6, Coq7, Coq8, and Coq9 GFP fusion proteins also localized to the mitochondria PMID:11092853 Ppt1-green fluorescent protein fusion proteins localized to the mitochondria, indicating that ubiquinone biosynthesis occurs in the mitochondria in S. pombe. |
| GO:0005743 mitochondrial inner membrane | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT inference; consistent. Reason: IBA from PAINT node PTN000114161 (PTHR11048, GO_REF:0000033). Inner-membrane location is supported by two independent lines: Ppt1 is a polytopic UbiA-family membrane protein with a cleavable N-terminal transit peptide (UniProt FT TRANSIT 1..20, multi-pass membrane protein), and its single-gene GFP localisation is mitochondrial (PMID:11092853, PMID:24911838); the S. cerevisiae ortholog Coq2 carries EXP inner-membrane evidence in its COQ2 review. Core location of the activity. Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Mitochondrion inner membrane {ECO:0000255|HAMAP-Rule:MF_03189, file:SCHPO/ppt1/ppt1-uniprot.txt Multi-pass membrane protein PMID:11092853 Ppt1-green fluorescent protein fusion proteins localized to the mitochondria, indicating that ubiquinone biosynthesis occurs in the mitochondria in S. pombe. |
| GO:0005743 mitochondrial inner membrane | IDA PMID:11092853 Phenotypes of fission yeast defective in ubiquinone producti... | ACCEPT | Summary: PomBase IDA for inner-membrane location from the Ppt1-GFP study. Reason: The cached full text of PMID:11092853 shows Ppt1-GFP in mitochondria and does not itself fractionate sub-compartments, so the inner-membrane resolution reflects the curator's reading with UniProt (which tags its inner-membrane line with this paper). The claim is correct on the topology and ortholog evidence, so the row is accepted rather than second-guessed. Inner-membrane location is supported by two independent lines: Ppt1 is a polytopic UbiA-family membrane protein with a cleavable N-terminal transit peptide (UniProt FT TRANSIT 1..20, multi-pass membrane protein), and its single-gene GFP localisation is mitochondrial (PMID:11092853, PMID:24911838); the S. cerevisiae ortholog Coq2 carries EXP inner-membrane evidence in its COQ2 review. Core location of the activity. Supporting Evidence: PMID:11092853 Ppt1-green fluorescent protein fusion proteins localized to the mitochondria, indicating that ubiquinone biosynthesis occurs in the mitochondria in S. pombe. file:SCHPO/ppt1/ppt1-uniprot.txt Mitochondrion inner membrane {ECO:0000255|HAMAP-Rule:MF_03189, ECO:0000269|PubMed:11092853}; Multi-pass membrane protein |
| GO:0005743 mitochondrial inner membrane | IEA GO_REF:0000120 | ACCEPT | Summary: UniProt mapping; consistent. Reason: UniProt SubCell/UniRule mapping (GO_REF:0000120). Inner-membrane location is supported by two independent lines: Ppt1 is a polytopic UbiA-family membrane protein with a cleavable N-terminal transit peptide (UniProt FT TRANSIT 1..20, multi-pass membrane protein), and its single-gene GFP localisation is mitochondrial (PMID:11092853, PMID:24911838); the S. cerevisiae ortholog Coq2 carries EXP inner-membrane evidence in its COQ2 review. Core location of the activity. Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Mitochondrion inner membrane {ECO:0000255|HAMAP-Rule:MF_03189, file:SCHPO/ppt1/ppt1-uniprot.txt Multi-pass membrane protein PMID:11092853 Ppt1-green fluorescent protein fusion proteins localized to the mitochondria, indicating that ubiquinone biosynthesis occurs in the mitochondria in S. pombe. |
| GO:0006744 ubiquinone biosynthetic process | EXP PMID:17069919 Phenotypes and fed-batch fermentation of ubiquinone-overprod... | ACCEPT | Summary: ppt1 overexpression raises ubiquinone production (curator). Reason: The cached record for PMID:17069919 is abstract-only; it shows that ppt1 overexpression raises ubiquinone content, consistent with the curator's full-text EXP call. UniProt FUNCTION places Ppt1 in CoQ biosynthesis on experimental grounds (PMID:11092853). Core process. Supporting Evidence: PMID:17069919 we cloned and overexpressed the full-length ppt1 (MTppt1) gene, which encodes p-hydroxybenzoate:polyprenyltransferase PMID:17069919 The yeast MTppt1 and ERppt1 transgenic lines showed about 3.7 and 5.1 times increment in UQ content file:SCHPO/ppt1/ppt1-uniprot.txt Mediates the second step in the final reaction sequence of coenzyme Q (CoQ) biosynthesis |
| GO:0006744 ubiquinone biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT inference; ubiquinone biosynthesis step. Reason: IBA from PAINT node PTN000114231 (PTHR11048, GO_REF:0000033). PAINT placement is consistent with S. pombe data: ppt1 disruption abolishes ubiquinone-10 production, which S. cerevisiae COQ2 restores (PMID:11092853). Ppt1 catalyses the prenylation step, so it does part of the work of the process. Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Mediates the second step in the final reaction sequence of coenzyme Q (CoQ) biosynthesis PMID:11092853 Expression of COQ2 from Saccharomyces cerevisiae in the defective S. pombe strain restored growth and enabled the cells to produce ubiquinone-10, indicating that COQ2 and ppt1 are functional homologs. |
| GO:0006744 ubiquinone biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: Mapping; consistent. Reason: UniRule/UniPathway mapping (GO_REF:0000120). Consistent with the experimentally supported UniProt FUNCTION and PATHWAY statements and with the IMP rows. Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Mediates the second step in the final reaction sequence of coenzyme Q (CoQ) biosynthesis file:SCHPO/ppt1/ppt1-uniprot.txt PATHWAY: Cofactor biosynthesis; ubiquinone biosynthesis. |
| GO:0006744 ubiquinone biosynthetic process | IMP PMID:11092853 Phenotypes of fission yeast defective in ubiquinone producti... | ACCEPT | Summary: ppt1 disruption abolishes ubiquinone production. Reason: The ppt1 disruptant makes no UQ-10, and either ppt1 or S. cerevisiae COQ2 restores UQ-10 (PMID:11092853). Ppt1 catalyses the prenylation step; core process. Supporting Evidence: PMID:11092853 When we extracted ubiquinone from each strain, UQ-10 was detected in the wild-type strain, in NU609 harboring pREP1-PPT1, and in NU609 harboring pREP1-COQ2, but not in NU609 alone PMID:11092853 Expression of COQ2 from Saccharomyces cerevisiae in the defective S. pombe strain restored growth and enabled the cells to produce ubiquinone-10, indicating that COQ2 and ppt1 are functional homologs. |
| GO:0006744 ubiquinone biosynthetic process | IMP PMID:24911838 Functional conservation of coenzyme Q biosynthetic genes amo... | ACCEPT | Summary: ppt1 disruption abolishes ubiquinone production. Reason: The ppt1 deletion lacks CoQ10, shares the coq-mutant phenotypes, and is complemented by human COQ2 (PMID:24911838). 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 All of the HsCOQ2 constructs restored the growth of the S. pombe Ξppt1 strain (data not shown) and recovered its defective production of CoQ10 (Figure 5B). |
| GO:0008299 isoprenoid biosynthetic process | IEA GO_REF:0000104 | KEEP AS NON CORE | Summary: Broad process; Ppt1 attaches the polyprenyl (isoprenoid) side chain to 4-hydroxybenzoate in CoQ synthesis. Reason: UniRule mapping (GO_REF:0000104). Ppt1 condenses all-trans polyprenyl diphosphate with 4-hydroxybenzoate, forming the prenylated (isoprenoid-containing) first CoQ intermediate (UniProt function, ECO:0000269 PubMed:11092853 and HAMAP MF_03189). The term is defensible but peripheral and is not an ancestor of ubiquinone biosynthetic process (GO:0006744), which carries the core process, so it stays non-core rather than MODIFY. Same action as the S. cerevisiae COQ2 row. Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Catalyzes the prenylation of para-hydroxybenzoate (PHB) with an all-trans polyprenyl group. file:SCHPO/ppt1/ppt1-uniprot.txt Mediates the second step in the final reaction sequence of coenzyme Q (CoQ) biosynthesis, which is the condensation of the polyisoprenoid side chain with PHB, generating the first membrane-bound Q intermediate. |
| GO:0008412 4-hydroxybenzoate polyprenyltransferase activity | EXP PMID:17069919 Phenotypes and fed-batch fermentation of ubiquinone-overprod... | ACCEPT | Summary: ppt1-dependent ubiquinone overproduction (curator, full text). Reason: The cached abstract of PMID:17069919 states that ppt1 encodes the polyprenyltransferase and that its overexpression raises UQ content; it does not report a direct enzyme assay, so the activity call defers to the curator's full-text reading. UniProt FUNCTION (ECO:0000269 PubMed:11092853) gives the PHB prenylation reaction. Core function. Supporting Evidence: PMID:17069919 we cloned and overexpressed the full-length ppt1 (MTppt1) gene, which encodes p-hydroxybenzoate:polyprenyltransferase PMID:17069919 The yeast MTppt1 and ERppt1 transgenic lines showed about 3.7 and 5.1 times increment in UQ content file:SCHPO/ppt1/ppt1-uniprot.txt Catalyzes the prenylation of para-hydroxybenzoate (PHB) with an all-trans polyprenyl group. |
| GO:0008412 4-hydroxybenzoate polyprenyltransferase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT inference. Reason: IBA from PAINT node PTN000868285 (PTHR11048, GO_REF:0000033). Family membership (PANTHER PTHR11048:SF28) and the S. pombe complementation result (COQ2 restores ubiquinone-10 synthesis in the ppt1 disruptant, PMID:11092853) support the inherited activity. Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Catalyzes the prenylation of para-hydroxybenzoate (PHB) with an all-trans polyprenyl group. file:SCHPO/ppt1/ppt1-uniprot.txt PTHR11048:SF28; 4-HYDROXYBENZOATE POLYPRENYLTRANSFERASE, MITOCHONDRIAL PMID:11092853 Expression of COQ2 from Saccharomyces cerevisiae in the defective S. pombe strain restored growth and enabled the cells to produce ubiquinone-10, indicating that COQ2 and ppt1 are functional homologs. |
| GO:0008412 4-hydroxybenzoate polyprenyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: EC mapping. Reason: EC/Rhea, ARBA and UniRule mapping (GO_REF:0000120). EC/RHEA mapping consistent with UbiA family membership (TIGR01474) and the experimentally supported UniProt FUNCTION. Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Catalyzes the prenylation of para-hydroxybenzoate (PHB) with an all-trans polyprenyl group. file:SCHPO/ppt1/ppt1-uniprot.txt Belongs to the UbiA prenyltransferase family. file:SCHPO/ppt1/ppt1-uniprot.txt TIGR01474; ubiA_proteo |
| GO:0008412 4-hydroxybenzoate polyprenyltransferase activity | IMP PMID:11092853 Phenotypes of fission yeast defective in ubiquinone producti... | ACCEPT | Summary: ppt1 encodes PHB polyprenyl transferase; S. cerevisiae COQ2 complements the disruption. Reason: The ppt1 disruptant makes no UQ-10, and S. cerevisiae COQ2, the characterised PHB polyprenyltransferase, complements it (PMID:11092853). UniProt FUNCTION and CATALYTIC ACTIVITY carry ECO:0000269 from this paper. Core function. Supporting Evidence: PMID:11092853 p-Hydroxybenzoate (PHB) polyprenyl diphosphate transferase catalyzes the condensation of PHB and polyprenyl diphosphate in ubiquinone biosynthesis. We isolated the gene (designated ppt1) encoding PHB polyprenyl diphosphate transferase from Schizosaccharomyces pombe and constructed a strain with a disrupted ppt1 gene. PMID:11092853 Expression of COQ2 from Saccharomyces cerevisiae in the defective S. pombe strain restored growth and enabled the cells to produce ubiquinone-10, indicating that COQ2 and ppt1 are functional homologs. file:SCHPO/ppt1/ppt1-uniprot.txt Catalyzes the prenylation of para-hydroxybenzoate (PHB) with an all-trans polyprenyl group. |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: Generic membrane from InterPro2GO; correct but general. Ppt1 is a polytopic mitochondrial inner-membrane protein. Reason: InterPro2GO mapping (GO_REF:0000002). Correct but general: Ppt1 is a multi-pass UbiA-family membrane protein in the mitochondrial inner membrane (UniProt, HAMAP MF_03189 with PMID:11092853), and the gene already carries GO:0005743 mitochondrial inner membrane. MODIFY to that term, matching the S. cerevisiae and human COQ2 reviews. Proposed replacements: mitochondrial inner membrane Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Mitochondrion inner membrane {ECO:0000255|HAMAP-Rule:MF_03189, file:SCHPO/ppt1/ppt1-uniprot.txt Multi-pass membrane protein |
| GO:0016765 transferase activity, transferring alkyl or aryl (other than methyl) groups | IEA GO_REF:0000002 | MODIFY | Summary: Generic InterPro-derived parent of the specific activity, which is already annotated. Reason: InterPro2GO mapping (GO_REF:0000002, IPR000537). Alkyl/aryl-transferase activity is correct but general; the specific activity, 4-hydroxybenzoate polyprenyltransferase (EC 2.5.1.39), is supported for S. pombe Ppt1 by UniProt's curated function and catalytic activity (ECO:0000269 PubMed:11092853, with HAMAP MF_03189) and by membership of the UbiA prenyltransferase family (Pfam PF01040). The gene already carries GO:0008412 with experimental support. Same MODIFY as the S. cerevisiae and human COQ2 reviews. Proposed replacements: 4-hydroxybenzoate polyprenyltransferase activity Supporting Evidence: file:SCHPO/ppt1/ppt1-uniprot.txt Reaction=an all-trans-polyprenyl diphosphate + 4-hydroxybenzoate = a 4-hydroxy-3-(all-trans-polyprenyl)benzoate + diphosphate; file:SCHPO/ppt1/ppt1-uniprot.txt Pfam; PF01040; UbiA; 1. |
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