MCT1 (YOR221C) encodes the mitochondrial malonyl-CoA:acyl carrier protein transacylase (FabD family, EC 2.3.1.39) of S. cerevisiae. It transfers the malonyl group from malonyl-CoA, made in the matrix by the acetyl-CoA carboxylase Hfa1, onto the phosphopantetheine arm of the mitochondrial acyl carrier protein Acp1. The resulting malonyl-ACP is the two-carbon donor for the type II mitochondrial fatty acid synthase (with Cem1, Oar1, Htd2 and Etr1), which produces octanoyl-ACP for lipoic acid synthesis and other acyl chains needed for respiratory function. mct1 disruption causes respiratory deficiency, as in other mtFAS mutants.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004314 [acyl-carrier-protein] S-malonyltransferase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from FabD node PTN002448244 (E. coli FabD, M. tuberculosis FabD, human MCAT), with Mct1 itself among the sources. Core MF. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt SIMILARITY: Belongs to the FabD family. file:yeast/MCT1/MCT1-uniprot.txt Reaction=holo-[ACP] + malonyl-CoA = malonyl-[ACP] + CoA; |
| GO:0004314 [acyl-carrier-protein] S-malonyltransferase activity | IEA GO_REF:0000003 | ACCEPT | Summary: IEA via EC 2.3.1.39 mapping. Correct for Mct1. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt Reaction=holo-[ACP] + malonyl-CoA = malonyl-[ACP] + CoA; |
| GO:0004314 [acyl-carrier-protein] S-malonyltransferase activity | IMP PMID:9388293 Two genes of the putative mitochondrial fatty acid synthase ... | ACCEPT | Summary: IMP (Schneider et al. 1997): MCT1 was identified by homology to bacterial malonyl-CoA:ACP transferases and its disruption causes respiratory deficiency like other mtFAS mutants. The abstract does not report enzymology, but the curator-assigned activity is consistent with FabD homology and UniProt; defer to curator. Core MF. Supporting Evidence: PMID:9388293 homologous to bacterial 3-oxoacyl-(acyl carrier protein) reductases and to malonyl-CoA:ACP-transferases, respectively PMID:9388293 We disrupted these two genes which in both cases led to a respiratory deficient phenotype |
| GO:0004314 [acyl-carrier-protein] S-malonyltransferase activity | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways PWY3O-10 (fatty acid biosynthesis, initial steps). Malonyl-CoA:ACP transacylase activity is correct for Mct1, but YeastPathways places it in the cytosolic FAS pathway, where malonyl transfer is done by the MPT domain of Fas1; Mct1 acts in mitochondrial FAS. MF accepted; compartment wrong. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt Reaction=holo-[ACP] + malonyl-CoA = malonyl-[ACP] + CoA; PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0004314 [acyl-carrier-protein] S-malonyltransferase activity | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways PWY3O-5962 (superpathway of fatty acid biosynthesis, saturated and unsaturated). Malonyl-CoA:ACP transacylase activity is correct for Mct1, but YeastPathways places it in the cytosolic FAS pathway, where malonyl transfer is done by the MPT domain of Fas1; Mct1 acts in mitochondrial FAS. MF accepted; compartment wrong. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt Reaction=holo-[ACP] + malonyl-CoA = malonyl-[ACP] + CoA; PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0004314 [acyl-carrier-protein] S-malonyltransferase activity | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways PWY3O-6336 (superpathway of fatty acid biosynthesis, saturated). Malonyl-CoA:ACP transacylase activity is correct for Mct1, but YeastPathways places it in the cytosolic FAS pathway, where malonyl transfer is done by the MPT domain of Fas1; Mct1 acts in mitochondrial FAS. MF accepted; compartment wrong. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt Reaction=holo-[ACP] + malonyl-CoA = malonyl-[ACP] + CoA; PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0005739 mitochondrion | HDA PMID:16823961 Toward the complete yeast mitochondrial proteome: multidimen... | ACCEPT | Summary: HDA mitochondrial proteomics (PMID:16823961) detecting Mct1. Correct; core location. Supporting Evidence: PMID:16823961 A total of 851 different proteins (PROMITO dataset) were identified |
| GO:0005739 mitochondrion | HDA PMID:24769239 Quantitative variations of the mitochondrial proteome and ph... | ACCEPT | Summary: HDA mitochondrial proteomics (PMID:24769239) detecting Mct1. Correct; core location. Supporting Evidence: PMID:24769239 quantitative proteomic and phosphoproteomic study of isolated mitochondria |
| GO:0005739 mitochondrion | IBA GO_REF:0000033 | ACCEPT | Summary: IBA (is_active_in) from PTN000104898 (Mct1, human MCAT). Correct. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0005739 mitochondrion | IEA GO_REF:0000044 | ACCEPT | Summary: IEA from UniProt subcellular location (Mitochondrion). Correct. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion |
| GO:0005739 mitochondrion | IMP PMID:9388293 Two genes of the putative mitochondrial fatty acid synthase ... | ACCEPT | Summary: IMP (Schneider et al. 1997): mct1 disruption gives a respiratory-deficient phenotype like other mtFAS genes. The location is better supported by proteomics, but the assignment is consistent with all data. Supporting Evidence: PMID:9388293 We disrupted these two genes which in both cases led to a respiratory deficient phenotype PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: RCA (is_active_in) from YeastPathways PWY3O-10 (fatty acid biosynthesis, initial steps) placing Mct1 in the cytosolic FAS pathway. Mct1 is mitochondrial; the cytosolic malonyl-transferase step is catalysed by the Fas1 MPT domain. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: RCA (is_active_in) from YeastPathways PWY3O-5962 (superpathway of fatty acid biosynthesis, saturated and unsaturated) placing Mct1 in the cytosolic FAS pathway. Mct1 is mitochondrial; the cytosolic malonyl-transferase step is catalysed by the Fas1 MPT domain. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0005829 cytosol | RCA GO_REF:0000123 | REMOVE | Summary: RCA (is_active_in) from YeastPathways PWY3O-6336 (superpathway of fatty acid biosynthesis, saturated) placing Mct1 in the cytosolic FAS pathway. Mct1 is mitochondrial; the cytosolic malonyl-transferase step is catalysed by the Fas1 MPT domain. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0006631 fatty acid metabolic process | IMP PMID:9388293 Two genes of the putative mitochondrial fatty acid synthase ... | TOO GENERAL | Summary: IMP (Schneider et al. 1997). Correct but less specific than fatty acid biosynthetic process, which is the role of Mct1 in mtFAS. Reason: Correct but less specific parent of the core BP. Supporting Evidence: PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase PMID:9388293 We disrupted these two genes which in both cases led to a respiratory deficient phenotype |
| GO:0006633 fatty acid biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from FabD node PTN002448244. Mct1 loads malonyl units onto mitochondrial ACP for mtFAS; core BP. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt FUNCTION: Involved in biosynthesis of fatty acids in mitochondria. PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0006633 fatty acid biosynthetic process | IEA GO_REF:0000041 | ACCEPT | Summary: IEA from UniPathway UPA00094 (fatty acid biosynthesis). Correct. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt FUNCTION: Involved in biosynthesis of fatty acids in mitochondria. |
| GO:0006633 fatty acid biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways PWY3O-10 (fatty acid biosynthesis, initial steps). BP correct (mitochondrial rather than cytosolic FAS). Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt FUNCTION: Involved in biosynthesis of fatty acids in mitochondria. PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0006633 fatty acid biosynthetic process | RCA GO_REF:0000123 | ACCEPT | Summary: RCA from YeastPathways PWY3O-5962 (superpathway of fatty acid biosynthesis, saturated and unsaturated). BP correct (mitochondrial rather than cytosolic FAS). Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt FUNCTION: Involved in biosynthesis of fatty acids in mitochondria. PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase |
| GO:0016740 transferase activity | IEA GO_REF:0000002 | TOO GENERAL | Summary: IEA from InterPro IPR001227 (acyl transferase domain). Correct but uninformative parent of the malonyltransferase activity. Reason: Uninformative parent of the core MF. Supporting Evidence: file:yeast/MCT1/MCT1-uniprot.txt SIMILARITY: Belongs to the FabD family. |
| GO:0019367 fatty acid elongation, saturated fatty acid | RCA GO_REF:0000123 | MARK AS OVER ANNOTATED | Summary: RCA from YeastPathways PWY3O-6336 (superpathway of fatty acid biosynthesis, saturated), a cytosolic superpathway. Mct1 supplies malonyl-ACP to mitochondrial FAS, whose main product is the octanoyl lipoate precursor; involvement in cytosolic saturated-fatty-acid elongation is not supported. Reason: Inherited from a cytosolic superpathway. Supporting Evidence: PMID:9388293 They are presumed to be part of a type-II mitochondrial fatty acid synthase PMID:19571038 Mitochondrial fatty acid synthesis (FAS) generates the octanoyl-group that is required for the synthesis of lipoic acid |
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Download this section (compressed HTML)Q: Has the malonyl-CoA:ACP transacylase activity of yeast Mct1 been measured directly with purified protein and holo-Acp1?
Experiment: In vitro assay of recombinant Mct1 with malonyl-CoA and yeast holo-Acp1, with active-site serine mutant as control, and rescue of mct1 respiratory deficiency.
Predicted malonyl-CoA:ACP transferase; putative component of a type-II mitochondrial fatty acid synthase that produces intermediates for phospholipid remodeling
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