Zwf1 (YNL241C, also MET19) is the sole glucose-6-phosphate 1-dehydrogenase (G6PD, EC 1.1.1.49) of Saccharomyces cerevisiae. It oxidises D-glucose 6-phosphate to 6-phospho-D-glucono-1,5-lactone with reduction of NADP+, the first and rate-controlling step of the oxidative pentose phosphate pathway, and is a principal source of cytosolic NADPH. zwf1 null mutants grow normally on rich glucose media but require an organic sulfur source (methionine, cysteine, AdoMet or glutathione), reflecting the NADPH demand of sulfate assimilation, and are hypersensitive to hydrogen peroxide and other oxidants, with a lowered cytosolic NADPH/NADP+ ratio, poor glutathione recycling and failure to mount an adaptive response to H2O2. Loss of Zwf1 suppresses the glucose-negative phenotype of 6-phosphogluconate dehydrogenase mutants. ZWF1 transcription is repressed by elevated AdoMet. Zwf1 is a cytosolic protein homologous to human G6PD.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004345 glucose-6-phosphate dehydrogenase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA (PTN000604427) for G6PD activity; Zwf1 is the yeast member of the conserved G6PD family. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- PMID:2001672 Cloning of the MET19 gene revealed that it encodes the glucose-6-phosphate dehydrogenase from yeast. |
| GO:0004345 glucose-6-phosphate dehydrogenase activity | IEA GO_REF:0000120 | ACCEPT | Summary: EC 1.1.1.49 / RHEA:15841 / InterPro G6PD signatures mapping; correct. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- |
| GO:0004345 glucose-6-phosphate dehydrogenase activity | IMP PMID:2001672 Identification of the structural gene for glucose-6-phosphat... | ACCEPT | Summary: Thomas et al.: MET19 encodes G6PD and its null mutant lacks the enzyme (IMP). Supporting Evidence: PMID:2001672 Cloning of the MET19 gene revealed that it encodes the glucose-6-phosphate dehydrogenase from yeast. PMID:2001672 The only phenotype of such a strain is an absolute requirement for an organic sulfur source, i.e. methionine, S-adenosylmethionine (AdoMet), cysteine, glutathione or homocysteine. |
| GO:0004345 glucose-6-phosphate dehydrogenase activity | IMP PMID:2269430 Isolation and characterization of the ZWF1 gene of Saccharom... | ACCEPT | Summary: Nogae and Johnston isolated ZWF1 as the G6PD structural gene; null mutants lack G6PD (IMP). Supporting Evidence: PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. PMID:2269430 Null mutants lacking G6PD appear to grow normally, but are more sensitive than wild type to oxidizing agents that presumably reduce the level of NADPH. |
| GO:0004345 glucose-6-phosphate dehydrogenase activity | ISS GO_REF:0000024 | ACCEPT | Summary: Manual ISS from human G6PD (P11413); consistent with the yeast mutant data. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. |
| GO:0004345 glucose-6-phosphate dehydrogenase activity | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (OXIDATIVEPENT-PWY) assigning G6P + NADP+ -> 6-phosphoglucono-lactone + NADPH (EC 1.1.1.49) to Zwf1; correct. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. |
| GO:0004345 glucose-6-phosphate dehydrogenase activity | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (PENTOSE-P-PWY superpathway), same reaction; correct. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. |
| GO:0005737 cytoplasm | HDA PMID:11914276 Subcellular localization of the yeast proteome. | ACCEPT | Summary: Kumar et al. HTP immunolocalization: cytoplasm. Correct for a PPP enzyme. Supporting Evidence: PMID:11914276 By high-throughput immunolocalization of tagged gene products, we have determined the subcellular localization of 2744 yeast proteins. |
| GO:0005737 cytoplasm | HDA PMID:14562095 Global analysis of protein localization in budding yeast. | ACCEPT | Summary: Huh et al. GFP-tagging screen: cytoplasm. Correct. Supporting Evidence: PMID:14562095 Here we describe the construction and analysis of a collection of yeast strains expressing full-length, chromosomally tagged green fluorescent protein fusion proteins. |
| GO:0005829 cytosol | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA (PTN000604429) for cytosol; consistent with cytoplasmic localization and the cytosolic NADPH phenotype of zwf1 cells. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Decreases the cytosolic NADPH/NADP(+) ratio; this PMID:14562095 Here we describe the construction and analysis of a collection of yeast strains expressing full-length, chromosomally tagged green fluorescent protein fusion proteins. |
| GO:0005829 cytosol | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (OXIDATIVEPENT-PWY) is_active_in cytosol; correct. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Decreases the cytosolic NADPH/NADP(+) ratio; this |
| GO:0005829 cytosol | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (PENTOSE-P-PWY) is_active_in cytosol; correct. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Decreases the cytosolic NADPH/NADP(+) ratio; this |
| GO:0006006 glucose metabolic process | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: PAINT IBA for glucose metabolic process. Zwf1 oxidises glucose 6-phosphate, so it participates in glucose catabolism via the PPP, but the term is broad; the oxidative PPP term captures the role. Reason: Broad parent-level process; oxidative PPP is the informative term. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. |
| GO:0006006 glucose metabolic process | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: InterPro G6PD signatures (IPR001282 etc.) mapped to glucose metabolic process; true but general. Reason: Broad parent-level process; oxidative PPP is the informative term. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- |
| GO:0006098 pentose-phosphate shunt | IEA GO_REF:0000041 | ACCEPT | Summary: UniPathway UPA00115 mapping to pentose-phosphate shunt; correct (oxidative branch is more precise). Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt ribulose 5-phosphate from D-glucose 6-phosphate (oxidative stage): step PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. |
| GO:0006098 pentose-phosphate shunt | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (PENTOSE-P-PWY); correct. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt ribulose 5-phosphate from D-glucose 6-phosphate (oxidative stage): step PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. |
| GO:0006740 NADPH regeneration | IMP PMID:2269430 Isolation and characterization of the ZWF1 gene of Saccharom... | ACCEPT | Summary: Nogae and Johnston: zwf1 nulls are oxidant-sensitive, implicating G6PD as a major NADPH source; later work showed a decreased cytosolic NADPH/NADP+ ratio in zwf1 cells. NADPH regeneration is a core role of Zwf1. Supporting Evidence: PMID:2269430 Null mutants lacking G6PD appear to grow normally, but are more sensitive than wild type to oxidizing agents that presumably reduce the level of NADPH. PMID:2269430 This suggests that G6PD has a major role in NADPH production in yeast. file:yeast/ZWF1/ZWF1-uniprot.txt Decreases the cytosolic NADPH/NADP(+) ratio; this |
| GO:0009051 pentose-phosphate shunt, oxidative branch | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA for the oxidative branch; Zwf1 catalyses its first step. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt ribulose 5-phosphate from D-glucose 6-phosphate (oxidative stage): step PMID:2269430 Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first step of the pentose phosphate pathway, a reaction that generates NADPH. |
| GO:0009051 pentose-phosphate shunt, oxidative branch | IMP PMID:7045591 Pentose phosphate pathway mutants of yeast. | ACCEPT | Summary: Lobo and Maitra: loss of G6PD suppresses the glucose-negative phenotype of 6-phosphogluconate dehydrogenase mutants, genetically placing Zwf1 upstream in the oxidative PPP (IMP). Supporting Evidence: PMID:7045591 Suppression of this mutant for growth on glucose takes place by the loss of glucose 6-phosphate dehydrogenase. |
| GO:0009051 pentose-phosphate shunt, oxidative branch | IMP PMID:8299150 Pentose-phosphate pathway in Saccharomyces cerevisiae: analy... | ACCEPT | Summary: Schaaff-Gerstenschlager and Zimmermann: zwf1 combined with tkl1 (and tal1) impairs growth, partly rescued by xylulose, consistent with Zwf1 feeding pentose phosphates through the oxidative branch. Supporting Evidence: PMID:8299150 Only the tkl1 zwf1 double and the tal1 tkl1 zwf1 triple mutant grew more slowly than the wild-type in rich medium. |
| GO:0009051 pentose-phosphate shunt, oxidative branch | RCA GO_REF:0000123 | ACCEPT | Summary: YeastPathways RCA (OXIDATIVEPENT-PWY); correct. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt ribulose 5-phosphate from D-glucose 6-phosphate (oxidative stage): step file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- |
| GO:0016614 oxidoreductase activity, acting on CH-OH group of donors | IEA GO_REF:0000002 | MODIFY | Summary: InterPro IPR001282 (G6PD) mapping to oxidoreductase activity acting on CH-OH donors; correct but a distant ancestor of the known specific activity. Reason: Too general; the specific activity GO:0004345 is established for Zwf1. Proposed replacements: glucose-6-phosphate dehydrogenase activity Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- PMID:2001672 Cloning of the MET19 gene revealed that it encodes the glucose-6-phosphate dehydrogenase from yeast. |
| GO:0042542 response to hydrogen peroxide | IMP PMID:7586028 Mutants of Saccharomyces cerevisiae sensitive to oxidative a... | KEEP AS NON CORE | Summary: Krems et al.: a peroxide-sensitive pos complementation group was allelic to ZWF1/MET19, i.e. loss of Zwf1 causes H2O2 sensitivity. This reflects Zwf1's NADPH supply to antioxidant systems rather than a dedicated stress-response function. Reason: Downstream phenotype of NADPH supply; physiologically important but not core. Supporting Evidence: PMID:7586028 One complementation group lacked glucose-6-phosphate dehydrogenase and was shown to be allelic to the glucose-6-phosphate dehydrogenase structural gene ZWF1/MET19. |
| GO:0042542 response to hydrogen peroxide | IMP PMID:9480895 Importance of glucose-6-phosphate dehydrogenase in the adapt... | KEEP AS NON CORE | Summary: Izawa et al.: G6PD-deficient cells are H2O2-hypersensitive and fail to adapt to H2O2; the authors suggest roles beyond NADPH for glutathione reductase. Retain as a significant but non-core physiological role. Reason: Response to H2O2 is a consequence of NADPH provision; non-core. Supporting Evidence: PMID:9480895 Glucose-6-phosphate dehydrogenase (G6PDH)-deficient cells of Saccharomyces cerevisiae showed increased susceptibility and were unable to induce adaptation to oxidative stress. PMID:9480895 In S. cerevisiae, G6PDH appears to play other important roles in the adaptive response to H2O2 stress besides supplying NADPH to the GR reaction. |
| GO:0050661 NADP binding | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: InterPro G6PD NAD-binding/C-terminal domain mapping to NADP binding. Correct (NADP+ is the cosubstrate) but implied by the catalytic activity term. Reason: Cosubstrate binding subsumed by G6PD activity. Supporting Evidence: file:yeast/ZWF1/ZWF1-uniprot.txt Reaction=D-glucose 6-phosphate + NADP(+) = 6-phospho-D-glucono-1,5- |
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Experiment: Restore cytosolic NADPH in zwf1 cells with an orthogonal NADPH source (e.g. heterologous NADP-dependent dehydrogenase) and test whether H2O2 adaptation and organic-sulfur independence are rescued.
Glucose-6-phosphate dehydrogenase (G6PD); catalyzes the first step of the pentose phosphate pathway; involved in adaptation to oxidative stress; negative regulator of nonselective autophagy, independent of Stb5p; protein abundance increases in response to DNA replication stress; homolog of human G6PD which is deficient in patients with hemolytic anemia; human G6PD can complement yeast zwf1 null mutant
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