SPBC646.07c (PomBase tsc13) encodes the fission yeast very-long-chain enoyl-CoA reductase (trans-2-enoyl-CoA reductase, EC 1.3.1.38/1.3.1.93), a multi-pass endoplasmic reticulum membrane protein of the steroid 5-alpha-reductase family, orthologous to S. cerevisiae TSC13 and human TECR. It catalyses the NADPH-dependent reduction of trans-2-enoyl-CoA to the saturated acyl-CoA two carbons longer, the fourth and final step of each ER fatty-acid elongation cycle that also involves elo1/elo2, ifa38 and phs1. The resulting very-long-chain fatty acids are incorporated into ceramides and sphingolipids. Its function is inferred from orthology; ER localisation has been observed directly in a genome-wide S. pombe study.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005739 mitochondrion | ISO GO_REF:0000024 | MARK AS OVER ANNOTATED | Summary: PomBase ISO from S. cerevisiae TSC13, whose mitochondrial annotations come only from high-throughput mitochondrial proteomes (HDA), judged in the TSC13 review as likely ER contact-site co-purification. There is no S. pombe evidence for mitochondrial Tsc13 and no mitochondrial function. Reason: Transfer of a proteomics-only, probably contaminant location from the ortholog; the S. pombe protein is localised to the ER. Propagation Review Root cause: SOURCE WEAK OR INFERRED Failure modes: SOURCE EVIDENCE WEAK Sources checked: SGD:S000002173 · S000002173 SOURCE WEAK OR INFERRED TSC13 mitochondrial calls rest only on mitochondrial proteome HDA data. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane PMID:16823372 we determined the localization of 4,431 proteins |
| GO:0005783 endoplasmic reticulum | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | ACCEPT | Summary: ORFeome-wide YFP localisation (Matsuyama et al. 2006) placed SPBC646.07c at the ER; UniProt cites this study for ER membrane localisation. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins file:SCHPO/tsc13/tsc13-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane |
| GO:0005783 endoplasmic reticulum | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from node PTN000059180 (TECR clade; donors S. cerevisiae TSC13, human TECR, Arabidopsis ECR/CER10). ER residence is conserved and observed for the S. pombe protein. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane |
| GO:0005789 endoplasmic reticulum membrane | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular-location mapping (SL-0097), derived from experimental PMID:16823372 data; correct. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane |
| GO:0005789 endoplasmic reticulum membrane | ISO GO_REF:0000024 | ACCEPT | Summary: PomBase ISO from S. cerevisiae Tsc13, an experimentally characterised polytopic ER membrane protein; correct. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane |
| GO:0006629 lipid metabolic process | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO (IPR001104, 3-oxo-5-alpha-steroid 4-dehydrogenase C-terminal) to 'lipid metabolic process'; true but very general. Reason: The specific process is VLCFA biosynthesis; same call as in the S. cerevisiae TSC13 review. Proposed replacements: very long-chain fatty acid biosynthetic process Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + |
| GO:0006665 sphingolipid metabolic process | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: PAINT IBA from node PTN000059180 (TECR clade; donors S. cerevisiae TSC13, human TECR, Arabidopsis ECR/CER10). The enzyme supplies the VLCFA acyl chains of ceramide; sphingolipid metabolism is a downstream consequence. Reason: Downstream, non-core; consistent with the TSC13 review. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + |
| GO:0016627 oxidoreductase activity, acting on the CH-CH group of donors | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO (IPR001104) to the grouping term 'oxidoreductase activity, acting on the CH-CH group of donors'; correct but uninformative. Reason: Precise activity term exists. Proposed replacements: very-long-chain enoyl-CoA reductase activity Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + |
| GO:0019166 trans-2-enoyl-CoA reductase (NADPH) activity | IEA GO_REF:0000120 | MODIFY | Summary: Rhea/EC mapping (RHEA:33763, EC 1.3.1.38) to trans-2-enoyl-CoA reductase (NADPH). Correct reaction type, but the elongase enzyme acts on very-long-chain substrates; PomBase GO-CAM 678073a900002931 also uses GO:0019166. Reason: GO:0102758 is the specific very-long-chain activity of the ER elongase enoyl reductase; same call as in the S. cerevisiae TSC13 review. Proposed replacements: very-long-chain enoyl-CoA reductase activity Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + |
| GO:0030148 sphingolipid biosynthetic process | ISO GO_REF:0000024 | KEEP AS NON CORE | Summary: PomBase ISO from S. cerevisiae TSC13, whose mutants accumulate long-chain bases and ceramides with shortened acyl chains. Downstream of the VLCFA product. Reason: Non-core downstream process. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + |
| GO:0030497 fatty acid elongation | NAS GO_REF:0000051 | ACCEPT | Summary: PomBase keyword-mapping NAS for fatty acid elongation. Correct: the enoyl reduction completes each elongation cycle. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + |
| GO:0042761 very long-chain fatty acid biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from node PTN000059180 (TECR clade; donors S. cerevisiae TSC13, human TECR, Arabidopsis ECR/CER10). VLCFA biosynthesis is the core process. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + |
| GO:0102758 very-long-chain enoyl-CoA reductase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA from node PTN000059180 (TECR clade; donors S. cerevisiae TSC13, human TECR, Arabidopsis ECR/CER10). Very-long-chain enoyl-CoA reductase activity is experimentally shown for TSC13 and TECR and inherited by the S. pombe ortholog; core activity. Supporting Evidence: file:SCHPO/tsc13/tsc13-uniprot.txt Reaction=a (2E)-enoyl-CoA + NADPH + H(+) = a 2,3-saturated acyl-CoA + file:SCHPO/tsc13/tsc13-uniprot.txt SIMILARITY: Belongs to the steroid 5-alpha reductase family. |
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