OAC1 (YKL120W) encodes the mitochondrial oxaloacetate carrier, a member of the mitochondrial carrier (SLC25) family located in the inner mitochondrial membrane. Reconstituted Oac1 transports oxaloacetate, malonate, sulfate and thiosulfate by uniport and by exchange, and also transports alpha- and beta-isopropylmalate with high affinity. In vivo, Oac1 exports alpha-isopropylmalate (the first committed intermediate of leucine biosynthesis, made by mitochondrial Leu4) to the cytosol, probably in exchange for oxaloacetate; oac1 leu4 double mutants are leucine auxotrophs on fermentable carbon sources. It was originally proposed to import cytosolic oxaloacetate made by pyruvate carboxylase into mitochondria.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005739 mitochondrion | HDA PMID:16823961 Toward the complete yeast mitochondrial proteome: multidimen... | ACCEPT | Summary: HDA from a mitochondrial proteomics survey (Reinders et al. 2006) detecting Oac1 in purified mitochondria. Correct but less specific than the inner-membrane localization established for this carrier. Supporting Evidence: PMID:16823961 Toward the complete yeast mitochondrial proteome PMID:10428783 In S. cerevisiae, OAC is in inner mitochondrial membranes |
| GO:0005739 mitochondrion | HDA PMID:24769239 Quantitative variations of the mitochondrial proteome and ph... | ACCEPT | Summary: HDA from quantitative mitochondrial proteomics (Renvoise et al. 2014) detecting Oac1 in mitochondria. Correct; inner membrane is the more precise location. Supporting Evidence: PMID:24769239 Quantitative variations of the mitochondrial proteome and phosphoproteome PMID:10428783 In S. cerevisiae, OAC is in inner mitochondrial membranes |
| GO:0005743 mitochondrial inner membrane | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from the mitochondrial carrier PTN002515516 node. Oac1 is a canonical SLC25 carrier and is experimentally located in the inner membrane, so the inherited location is correct for this protein. Supporting Evidence: PMID:10428783 In S. cerevisiae, OAC is in inner mitochondrial membranes |
| GO:0005743 mitochondrial inner membrane | IDA PMID:10428783 Identification of the yeast mitochondrial transporter for ox... | ACCEPT | Summary: IDA (Palmieri et al. 1999): Oac1 was localized to inner mitochondrial membranes. This is the site where it carries out oxaloacetate/sulfate/alpha-isopropylmalate transport. Supporting Evidence: PMID:10428783 In S. cerevisiae, OAC is in inner mitochondrial membranes |
| GO:0005743 mitochondrial inner membrane | IEA GO_REF:0000044 | ACCEPT | Summary: IEA from UniProt subcellular location (inner membrane, multi-pass) mapped to GO. Consistent with the IDA evidence. Supporting Evidence: PMID:10428783 In S. cerevisiae, OAC is in inner mitochondrial membranes |
| GO:0015116 sulfate transmembrane transporter activity | IDA PMID:10428783 Identification of the yeast mitochondrial transporter for ox... | ACCEPT | Summary: IDA: reconstituted Oac1 transports sulfate (and thiosulfate), and oac1 deletion reduces mitochondrial sulfate transport. Sulfate is a genuine substrate and is used as counter-anion in the exchange assays, though its physiological significance is less clear than that of alpha-IPM/oxaloacetate. Supporting Evidence: PMID:10428783 demonstration that the proteoliposomes transport malonate, oxaloacetate, sulfate, and thiosulfate PMID:10428783 deletion of its gene greatly reduces transport of oxaloacetate sulfate, thiosulfate, and malonate |
| GO:0015131 oxaloacetate transmembrane transporter activity | IDA PMID:10428783 Identification of the yeast mitochondrial transporter for ox... | ACCEPT | Summary: IDA: reconstituted Oac1 transports oxaloacetate and deletion reduces mitochondrial oxaloacetate transport. This is the defining activity of the carrier and the likely counter-substrate for alpha-IPM export. Supporting Evidence: PMID:10428783 demonstration that the proteoliposomes transport malonate, oxaloacetate, sulfate, and thiosulfate PMID:10428783 deletion of its gene greatly reduces transport of oxaloacetate sulfate, thiosulfate, and malonate PMID:18682385 Oac1p is important for leucine biosynthesis on fermentable carbon sources catalyzing the export of alpha-IPM, probably in exchange for oxalacetate |
| GO:0015729 oxaloacetate transport | IDA PMID:10428783 Identification of the yeast mitochondrial transporter for ox... | ACCEPT | Summary: IDA for oxaloacetate transport (Palmieri et al. 1999). Correct; the transmembrane-specific child (GO:1902356, also present) captures the same process. Supporting Evidence: PMID:10428783 demonstration that the proteoliposomes transport malonate, oxaloacetate, sulfate, and thiosulfate PMID:10428783 The main physiological role of OAC appears to be to use the proton-motive force to take up into mitochondria oxaloacetate produced from pyruvate by cytoplasmic pyruvate carboxylase |
| GO:0022857 transmembrane transporter activity | IBA GO_REF:0000033 | MARK AS OVER ANNOTATED | Summary: IBA to the root transporter activity term from the mitochondrial carrier family node. Not wrong, but uninformative given experimentally determined, specific substrate activities (oxaloacetate, sulfate, malonate, isopropylmalate) for Oac1. Reason: Superseded by specific IDA transporter activities for the same protein. Propagation Review Root cause: NO FAILURE NON CORE Failure modes: GRANULARITY MISMATCH Supporting Evidence: PMID:18682385 Recombinant and reconstituted mitochondrial oxalacetate carrier (Oac1p) efficiently transported alpha-IPM in addition to its known substrates oxalacetate, sulfate, and malonate |
| GO:0034658 isopropylmalate transmembrane transporter activity | IDA PMID:18682385 alpha-Isopropylmalate, a leucine biosynthesis intermediate i... | ACCEPT | Summary: IDA (Marobbio et al. 2008): recombinant reconstituted Oac1 efficiently transports alpha-IPM (Km 75 uM), and genetics (oac1 leu4 leucine auxotrophy) shows that this export supplies cytosolic leucine synthesis. This is the role Oac1 fills in the branched-chain amino acid biosynthesis pathway. Supporting Evidence: PMID:18682385 Recombinant and reconstituted mitochondrial oxalacetate carrier (Oac1p) efficiently transported alpha-IPM in addition to its known substrates oxalacetate, sulfate, and malonate PMID:18682385 the double mutant DeltaOAC1DeltaLEU4 did not grow at all on fermentable substrates in the absence of leucine PMID:18682385 Oac1p is important for leucine biosynthesis on fermentable carbon sources catalyzing the export of alpha-IPM, probably in exchange for oxalacetate |
| GO:0034659 isopropylmalate transport | IDA PMID:18682385 alpha-Isopropylmalate, a leucine biosynthesis intermediate i... | ACCEPT | Summary: IDA: Oac1 transports alpha-IPM in reconstituted liposomes; physiologically it exports alpha-IPM from the matrix to the cytosol. Supporting Evidence: PMID:18682385 Recombinant and reconstituted mitochondrial oxalacetate carrier (Oac1p) efficiently transported alpha-IPM in addition to its known substrates oxalacetate, sulfate, and malonate PMID:18682385 Oac1p is important for leucine biosynthesis on fermentable carbon sources catalyzing the export of alpha-IPM, probably in exchange for oxalacetate |
| GO:0055085 transmembrane transport | IEA GO_REF:0000002 | TOO GENERAL | Summary: IEA from InterPro IPR002067 (mitochondrial carrier) to transmembrane transport. Correct but generic; specific transport processes are annotated separately. Supporting Evidence: file:yeast/OAC1/OAC1-uniprot.txt Antiporter that exchanges dicarboxylates and sulfur oxoanions |
| GO:1901239 malonate(1-) transmembrane transporter activity | IDA PMID:10428783 Identification of the yeast mitochondrial transporter for ox... | ACCEPT | Summary: IDA: reconstituted Oac1 transports malonate. Valid substrate activity, of uncertain physiological importance. Supporting Evidence: PMID:10428783 demonstration that the proteoliposomes transport malonate, oxaloacetate, sulfate, and thiosulfate PMID:10428783 deletion of its gene greatly reduces transport of oxaloacetate sulfate, thiosulfate, and malonate |
| GO:1901553 malonic acid transmembrane transport | IEA GO_REF:0000108 | ACCEPT | Summary: IEA by inter-ontology inference from the malonate transporter activity IDA. Consistent with that annotation. Supporting Evidence: PMID:10428783 demonstration that the proteoliposomes transport malonate, oxaloacetate, sulfate, and thiosulfate |
| GO:1902356 oxaloacetate(2-) transmembrane transport | IEA GO_REF:0000108 | ACCEPT | Summary: IEA by inter-ontology inference from the oxaloacetate transporter activity IDA. Consistent with the experimental data. Supporting Evidence: PMID:10428783 demonstration that the proteoliposomes transport malonate, oxaloacetate, sulfate, and thiosulfate PMID:10428783 deletion of its gene greatly reduces transport of oxaloacetate sulfate, thiosulfate, and malonate |
| GO:1902358 sulfate transmembrane transport | IDA PMID:10428783 Identification of the yeast mitochondrial transporter for ox... | ACCEPT | Summary: IDA: Oac1 mediates sulfate uniport/exchange across reconstituted membranes and deletion reduces mitochondrial sulfate transport. Supporting Evidence: PMID:10428783 demonstration that the proteoliposomes transport malonate, oxaloacetate, sulfate, and thiosulfate PMID:10428783 deletion of its gene greatly reduces transport of oxaloacetate sulfate, thiosulfate, and malonate |
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Experiment: Measure matrix and cytosolic alpha-IPM and oxaloacetate pools in oac1, leu4 and oac1 leu4 strains by compartment-resolved metabolomics on glucose and on non-fermentable carbon sources.
Mitochondrial inner membrane transporter; transports oxaloacetate, sulfate, thiosulfate, and isopropylmalate; member of the mitochondrial carrier family
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