aldo-1 encodes fructose-bisphosphate aldolase 1 (CE-1), one of two class I aldolase isozymes in C. elegans (the other being aldo-2/CE-2). The enzyme catalyzes the reversible cleavage of fructose-1,6-bisphosphate into glyceraldehyde-3-phosphate and dihydroxyacetone phosphate, a central step in glycolysis and gluconeogenesis. CE-1 has unique kinetic properties with a broad substrate specificity compared to CE-2. The protein is ubiquitously expressed and in body wall muscle localizes to dense bodies, thick filaments/M-lines, and ER/sarcoplasmic reticulum, consistent with a role in providing ATP near contractile structures. In vivo, aldo-1 is a critical component of compensatory glycolysis: it is transcriptionally upregulated in mitochondrial complex I mutants and its knockdown strongly shortens their lifespan, and it is part of HIF-1-linked hypoxia-adaptation and age-associated neuronal metabolic transcriptional programs.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004332 fructose-bisphosphate aldolase activity | IDA PMID:9056253 Caenorhabditis elegans has two isozymic forms, CE-1 and CE-2... | ACCEPT | Summary: Direct experimental evidence. Inoue et al. purified recombinant CE-1 and demonstrated FBP aldolase activity with KM of 16.7 uM for FBP. This is the core molecular function of aldo-1. Reason: Direct enzyme assay on purified recombinant protein with kinetic characterization Supporting Evidence: PMID:9056253 Two distinct types of cDNAs for fructose-1,6-bisphosphate (FBP) aldolase, Ce-1 and Ce-2, have been isolated from nematode Caenorhabditis elegans, and the respective recombinant aldolase isozymes, CE-1 and CE-2, have been purified and characterized file:worm/aldo-1/aldo-1-deep-research-bioreason-sft.md [BioReason confirms] GO:0004332 fructose-bisphosphate aldolase activity... the catalytic center is pinpointed by IPR029768...marking the lysine-dependent iminium chemistry that drives carbon-carbon bond cleavage/formation file:worm/aldo-1/aldo-1-deep-research-falcon.md catalyzes the cleavage of the substrate **fructose-1,6-bisphosphate (F1,6BP)** in glycolysis file:worm/aldo-1/aldo-1-deep-research-falcon.md the lysine at position 230 is the residue where Schiff base intermediates are formed |
| GO:0004332 fructose-bisphosphate aldolase activity | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference consistent with and redundant to the IDA annotation from PMID:9056253. Correct but redundant. Reason: Phylogenetic annotation is consistent with direct experimental evidence |
| GO:0004332 fructose-bisphosphate aldolase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Automated annotation from InterPro domain and Rhea reaction mapping. Correct and consistent with IDA evidence. Reason: Automated annotation correctly infers function from domain architecture |
| GO:0006096 glycolytic process | NAS PMID:9056253 Caenorhabditis elegans has two isozymic forms, CE-1 and CE-2... | ACCEPT | Summary: Non-traceable author statement. The Inoue et al. paper characterizes aldo-1 as an FBP aldolase, and FBP aldolase is a glycolytic enzyme by definition. The glycolytic role is well supported by the enzyme activity data. Falcon deep research adds in vivo functional support: aldo-1 is upregulated in mitochondrial complex I mutants (~3-fold in gas-1, ~6-fold in nuo-6) and its RNAi knockdown strongly shortens the lifespan of these mutants (up to 65% in gas-1, >85% in nuo-6), with the authors concluding these mutants rely heavily on glycolysis for energy production. This directly supports a glycolytic process role beyond the by-definition inference. Reason: FBP aldolase activity directly places the enzyme in the glycolytic pathway Supporting Evidence: PMID:9056253 CE-1 evolved to act as an intrinsic enzyme that exhibits a much broader substrate specificity than dose CE-2 file:worm/aldo-1/aldo-1-deep-research-falcon.md In *C. elegans* mitochondrial complex I mutants, aldo-1 is transcriptionally upregulated, consistent with a metabolic shift toward glycolysis file:worm/aldo-1/aldo-1-deep-research-falcon.md decreased **gas-1(fc21)** median lifespan by **up to 65%** file:worm/aldo-1/aldo-1-deep-research-falcon.md rely heavily on glycolysis for energy production |
| GO:0006096 glycolytic process | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference of glycolytic process involvement. Consistent with the NAS annotation and enzyme function. Reason: Phylogenetic annotation consistent with biochemical evidence |
| GO:0006096 glycolytic process | IEA GO_REF:0000120 | ACCEPT | Summary: Automated annotation from InterPro and UniPathway mapping. Correct and consistent with other evidence. Reason: Automated annotation correctly infers pathway membership |
| GO:0030388 fructose 1,6-bisphosphate metabolic process | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference. FBP is the direct substrate of aldo-1, so involvement in its metabolism is inherent to the enzyme's catalytic activity. Falcon deep research independently describes ALDO-1 as cleaving the substrate fructose-1,6-bisphosphate, consistent with this annotation. Reason: Follows directly from the enzyme's catalytic function on FBP Supporting Evidence: file:worm/aldo-1/aldo-1-deep-research-falcon.md catalyzes the cleavage of the substrate **fructose-1,6-bisphosphate (F1,6BP)** in glycolysis |
| GO:0042802 identical protein binding | IPI PMID:14704431 A map of the interactome network of the metazoan C. elegans. | KEEP AS NON CORE | Summary: Detected via high-throughput Y2H in the C. elegans interactome mapping project. Class I aldolases are known homotetramers, so self-interaction is expected. However, Y2H self-interactions can be artifacts, though this is biologically plausible. The annotation is kept as non-core since identical protein binding is a generic term that does not inform about specific function. Reason: Self-interaction is biologically plausible for a homotetrameric enzyme but identical protein binding is uninformative as a standalone annotation Supporting Evidence: PMID:14704431 more than 4000 interactions were identified from high-throughput, yeast two-hybrid (HT=Y2H) screens |
| GO:0042802 identical protein binding | IPI PMID:19123269 Empirically controlled mapping of the Caenorhabditis elegans... | KEEP AS NON CORE | Summary: Replicated self-interaction in the expanded WI-2007/WI8 interactome. Confirmation of the PMID:14704431 finding, but still a generic annotation. Reason: Replication adds confidence but identical protein binding remains uninformative Supporting Evidence: PMID:19123269 the resulting dataset (Worm Interactome 2007 or WI-2007) is similar in quality to low-throughput data curated from the literature |
| GO:0005829 cytosol | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference of cytosolic localization. Class I aldolases are soluble cytosolic enzymes, so this is well supported. Consistent with the cytoplasm ISS annotation but more specific. Falcon deep research notes that, while no direct C. elegans localization was retrieved, the strong family-level expectation places aldolase in cytosolic glycolysis. Reason: Soluble glycolytic enzyme expected in cytosol based on conserved properties Supporting Evidence: file:worm/aldo-1/aldo-1-deep-research-falcon.md the strong family-level expectation that aldolase participates in cytosolic glycolysis |
| GO:0005737 cytoplasm | ISS GO_REF:0000024 | ACCEPT | Summary: Transferred from ortholog (P05065, rabbit ALDOC). Cytoplasmic localization is expected for a soluble glycolytic enzyme. Consistent with cytosol IBA annotation but less specific. Reason: Cytoplasmic localization is well established for class I aldolases |
| GO:0000792 heterochromatin | ISS GO_REF:0000024 | KEEP AS NON CORE | Summary: Transferred from rabbit aldolase C ortholog (P05065). Aldolase has been reported to associate with heterochromatin in some vertebrate studies as a moonlighting function. However, this is a non-canonical localization for a glycolytic enzyme and direct evidence in C. elegans is lacking. The ISS transfer is questionable for this non-canonical function. Falcon deep research corroborates this caution: it notes that aldolase moonlighting/extracellular localizations described in broader reviews are not direct C. elegans ALDO-1 localization evidence. Reason: Heterochromatin association is a reported moonlighting function in vertebrates but lacks direct evidence in C. elegans; ISS transfer of non-canonical localization is weak Supporting Evidence: file:worm/aldo-1/aldo-1-deep-research-falcon.md broader aldolase reviews discuss intracellular (and sometimes extracellular “moonlighting”) localizations across organisms, but this is not direct *C. elegans* ALDO-1 localization evidence |
| GO:0005783 endoplasmic reticulum | HDA PMID:21611156 Determining the sub-cellular localization of proteins within... | ACCEPT | Summary: High-throughput GFP localization in body wall muscle. T05D4.1 was classified in Category 6 (Dense bodies, Thick filaments and/or M-lines, ER/SR). The ER/SR component of the localization pattern was observed. Validated with both Gateway and genomic clones. Reason: Direct GFP localization data from high-throughput study, validated by two independent cloning approaches Supporting Evidence: PMID:21611156 The sub-cellular localization for the T05D4.1::GFP (A, B)...proteins expressed from gateway clones using a muscle-specific promoter (A, B and C) or from genomic clones using endogenous promoters (B, D and F) |
| GO:0030017 sarcomere | HDA PMID:21611156 Determining the sub-cellular localization of proteins within... | ACCEPT | Summary: High-throughput GFP localization in body wall muscle. Category 6 includes dense bodies, thick filaments, and M-lines, all of which are sarcomeric structures. Consistent with the known association of glycolytic enzymes with sarcomeric structures in muscle. Reason: Direct GFP localization data showing sarcomeric localization pattern in body wall muscle Supporting Evidence: PMID:21611156 we verified the localization of several Gateway constructs by cloning and tagging the corresponding gene via conventional methods using genomic DNA instead of cDNA, and using endogenous promoters instead of our muscle specific promoter. We were able to confirm the same sub-cellular localization using both methods |
| GO:0055120 striated muscle dense body | HDA PMID:21611156 Determining the sub-cellular localization of proteins within... | ACCEPT | Summary: High-throughput GFP localization in body wall muscle. Dense bodies are the C. elegans equivalent of vertebrate Z-discs, where they anchor actin filaments to the cell membrane. Category 6 explicitly includes dense body localization. T05D4.1 was one of the proteins used to validate the approach (Figure 3). Reason: Direct GFP localization data with validation by both Gateway and genomic clone approaches; dense body localization is part of Category 6 Supporting Evidence: PMID:21611156 The sub-cellular localization for the T05D4.1::GFP (A, B)...proteins expressed from gateway clones using a muscle-specific promoter (A, B and C) or from genomic clones using endogenous promoters (B, D and F) |
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Download this section (compressed HTML)Q: Does aldo-1 form a glycolytic metabolon with other glycolytic enzymes at sarcomeric structures in C. elegans body wall muscle, analogous to what has been proposed in vertebrate striated muscle?
Suggested experts: Moerman DG
Q: What are the distinct physiological roles of aldo-1 (CE-1) versus aldo-2 (CE-2) in C. elegans, given their different kinetic properties and substrate specificities?
Suggested experts: Hori K
Q: Is the heterochromatin association observed for vertebrate aldolase orthologs conserved in C. elegans aldo-1, and does it have functional significance?
Q: Is aldo-1 a direct HIF-1 transcriptional target, and how is its upregulation coordinated across hypoxia (HIF-1 over-activation), mitochondrial complex I dysfunction, and age-associated neuronal metabolic decline?
Experiment: Co-immunoprecipitation or proximity ligation assay of aldo-1 with other glycolytic enzymes (e.g., phosphofructokinase, GAPDH, triosephosphate isomerase) in C. elegans body wall muscle lysates, combined with co-localization imaging at sarcomeric structures.
Hypothesis: aldo-1 forms a sarcomeric glycolytic metabolon in C. elegans body wall muscle
Type: co-immunoprecipitation and imaging
Experiment: Generate aldo-1 single mutants and aldo-1; aldo-2 double mutants to compare phenotypes. Measure glycolytic flux, energy metabolism, lifespan, and glucose sensitivity in each genotype. Given that aldo-2 RNAi causes embryonic lethality, test whether aldo-1 loss is similarly lethal or shows distinct phenotypes.
Hypothesis: aldo-1 and aldo-2 have non-redundant roles in C. elegans metabolism
Type: genetic analysis and metabolomics
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