elo1 (SPAC1639.01c) encodes one of the two ELO-family fatty acid elongases of fission yeast, a multi-pass integral membrane 3-ketoacyl-CoA synthase of the endoplasmic reticulum and nuclear envelope. It condenses an acyl-CoA with malonyl-CoA to form a 3-oxoacyl-CoA two carbons longer, the first and rate-limiting step of the ER fatty acid elongation cycle completed by the 3-ketoacyl-CoA reductase, dehydratase and enoyl-CoA reductase. Sequence similarity places it with budding-yeast ELO2/ELO3 (UniProt calls it putative fatty acid elongase 2), and it is a paralogue of the S. pombe very-long-chain elongase elo2, which produces the C24 acyl chain of the major t20:0/24:0 phytoceramide. Its own chain-length specificity and physiological contribution relative to elo2 have not been defined; activity is inferred from homology.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005634 nucleus | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | KEEP AS NON CORE | Summary: ORFeome YFP screen scored elo1 in the nucleus. For a multi-pass ER membrane protein this most likely reflects nuclear-envelope (nuclear rim) signal; elo1 has no nucleoplasmic role. Kept as a non-core, imprecise localization; nuclear membrane is the accurate term (also annotated EXP). Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins, corresponding to approximately 90% of the fission yeast proteome PMID:30975915 nuclear membranes; these are continuous with the endoplasmic reticulum membranes |
| GO:0005783 endoplasmic reticulum | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA00028672 prediction of ER. Correct but less precise than ER membrane. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Multi-pass membrane protein {ECO:0000255}. Endoplasmic reticulum |
| GO:0005789 endoplasmic reticulum membrane | EXP PMID:30975915 The very-long-chain fatty acid elongase Elo2 rescues lethal ... | ACCEPT | Summary: EXP (Kinugasa et al. 2019): fluorescent-tagged elongases localised to the ER/nuclear membrane system (UniProt cites this paper for elo1 ER membrane localization). Core location. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Multi-pass membrane protein {ECO:0000255}. Endoplasmic reticulum PMID:30975915 nuclear membranes; these are continuous with the endoplasmic reticulum membranes |
| GO:0005789 endoplasmic reticulum membrane | IBA GO_REF:0000033 | ACCEPT | Summary: IBA ER membrane from ELO/ELOVL node PTN000125390 (S. cerevisiae ELO1/2/3, human ELOVLs, elo1 and elo2 donors). Core location. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Multi-pass membrane protein {ECO:0000255}. Endoplasmic reticulum |
| GO:0005789 endoplasmic reticulum membrane | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt SubCell SL-0097 mapping (ER membrane, from PMID:30975915). Correct. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Multi-pass membrane protein {ECO:0000255}. Endoplasmic reticulum |
| GO:0005789 endoplasmic reticulum membrane | ISS GO_REF:0000024 | ACCEPT | Summary: ISS from human ELOVL4 (Q9GZR5). Correct; consistent with direct S. pombe data. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Multi-pass membrane protein {ECO:0000255}. Endoplasmic reticulum |
| GO:0005829 cytosol | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | MARK AS OVER ANNOTATED | Summary: ORFeome screen also scored cytosol. elo1 is a predicted multi-pass integral membrane protein localised experimentally to ER and nuclear membranes, so a cytosolic pool is implausible; the call likely reflects diffuse ER signal or overexpression. Not removed because it is a curated HDA, but marked as an over-annotation. Reason: Integral ER membrane protein; cytosol not a site of activity. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Multi-pass membrane protein {ECO:0000255}. Endoplasmic reticulum PMID:16823372 we determined the localization of 4,431 proteins, corresponding to approximately 90% of the fission yeast proteome |
| GO:0009922 fatty acid elongase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA fatty acid elongase activity from PTN000125390 (S. cerevisiae ELO1/ELO2/ELO3, human ELOVL1-7, S. pombe elo2 among donors). elo1 is an ELO-family 3-ketoacyl-CoA synthase with the conserved HxxHH motif region. Core MF. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Belongs to the ELO family. file:SCHPO/elo1/elo1-uniprot.txt Reaction=a very-long-chain acyl-CoA + malonyl-CoA + H(+) = a very-long- |
| GO:0009922 fatty acid elongase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA (InterPro IPR002076 ELO, RHEA:32727, EC 2.3.1.199). Correct. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Reaction=a very-long-chain acyl-CoA + malonyl-CoA + H(+) = a very-long- |
| GO:0009922 fatty acid elongase activity | ISS GO_REF:0000024 | ACCEPT | Summary: ISS from S. cerevisiae ELO2 (P25358), the basis of UniProt naming elo1 'Putative fatty acid elongase 2'. Correct at the activity level; substrate chain-length specificity of elo1 has not been determined. Core MF; PomBase GO-CAM also has elo1 enabling GO:0009922 in ER membrane. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt May be involved in the synthesis of very long chain fatty file:SCHPO/elo1/elo1-uniprot.txt Reaction=a very-long-chain acyl-CoA + malonyl-CoA + H(+) = a very-long- |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: InterPro IPR002076 (ELO family) mapping to membrane. Correct but imprecise; ER membrane is established. MODIFY as in the S. cerevisiae ELO2/ELO3 reviews. Reason: Use the specific ER membrane location. Proposed replacements: endoplasmic reticulum membrane Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt Multi-pass membrane protein {ECO:0000255}. Endoplasmic reticulum |
| GO:0019367 fatty acid elongation, saturated fatty acid | IBA GO_REF:0000033 | ACCEPT | Summary: IBA fatty acid elongation, saturated fatty acid (ELOVL1/3/4/6/7 donors). S. pombe elongases extend saturated acyl-CoAs to C24 for ceramide (t20:0/24:0 is the major species). Accepted, consistent with ELO2/ELO3 reviews. Supporting Evidence: PMID:30975915 t20:0/24:0 phytoceramide (a conjugate of C20:0 phytosphingosine and C24:0 fatty acid) is a major ceramide species in S. pombe file:SCHPO/elo1/elo1-uniprot.txt Reaction=a very-long-chain acyl-CoA + malonyl-CoA + H(+) = a very-long- |
| GO:0030148 sphingolipid biosynthetic process | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA sphingolipid biosynthetic process (S. cerevisiae ELO2/ELO3, Candida, mouse Elovl donors). VLCFAs made by the elongases are the acyl chains of ceramide; the elongase supplies a substrate rather than performing a sphingolipid-synthesis step. Non-core, as in the ELO2/ELO3 reviews. Supporting Evidence: PMID:30975915 t20:0/24:0 phytoceramide (a conjugate of C20:0 phytosphingosine and C24:0 fatty acid) is a major ceramide species in S. pombe |
| GO:0031965 nuclear membrane | EXP PMID:30975915 The very-long-chain fatty acid elongase Elo2 rescues lethal ... | KEEP AS NON CORE | Summary: EXP nuclear membrane (Kinugasa et al. 2019). The nuclear envelope is continuous with the ER and the paper characterises the nuclear-membrane elongase pool; acceptable, non-core relative to ER membrane. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt SUBCELLULAR LOCATION: Nucleus membrane {ECO:0000269|PubMed:30975915}; PMID:30975915 nuclear membranes; these are continuous with the endoplasmic reticulum membranes |
| GO:0031965 nuclear membrane | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: UniProt SubCell SL-0182 mapping from the same experimental data. Non-core (ER-continuous). Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt SUBCELLULAR LOCATION: Nucleus membrane {ECO:0000269|PubMed:30975915}; |
| GO:0034625 fatty acid elongation, monounsaturated fatty acid | IBA GO_REF:0000033 | MARK AS OVER ANNOTATED | Summary: IBA fatty acid elongation, monounsaturated fatty acid, from animal ELOVL1/3/7 and Dictyostelium donors. No evidence that elo1 elongates monounsaturated substrates; S. pombe VLCFAs are saturated. Marked over-annotated, as in ELO2/ELO3. Reason: Substrate specificity propagated from animal ELOVLs; not supported in fission yeast. Supporting Evidence: PMID:30975915 t20:0/24:0 phytoceramide (a conjugate of C20:0 phytosphingosine and C24:0 fatty acid) is a major ceramide species in S. pombe |
| GO:0034626 fatty acid elongation, polyunsaturated fatty acid | IBA GO_REF:0000033 | REMOVE | Summary: IBA fatty acid elongation, polyunsaturated fatty acid, from animal/trypanosome PUFA elongases (ELOVL2/5, etc.). S. pombe makes no polyunsaturated fatty acids (it has only the delta-9 desaturase ole1), so there is no PUFA substrate. Removed, as in the S. cerevisiae ELO1/ELO2/ELO3 reviews. Reason: No PUFAs in fission yeast; lineage-specific animal specificity over-propagated. Supporting Evidence: PMID:30975915 t20:0/24:0 phytoceramide (a conjugate of C20:0 phytosphingosine and C24:0 fatty acid) is a major ceramide species in S. pombe |
| GO:0042761 very long-chain fatty acid biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA very long-chain fatty acid biosynthetic process (ELO2/ELO3, ELOVL donors). Core BP; used as part_of for elo1 in the PomBase GO-CAM. Supporting Evidence: file:SCHPO/elo1/elo1-uniprot.txt May be involved in the synthesis of very long chain fatty PMID:30975915 t20:0/24:0 phytoceramide (a conjugate of C20:0 phytosphingosine and C24:0 fatty acid) is a major ceramide species in S. pombe |
Loading supporting content…
Download this section (compressed HTML)Q: What chain-length range does elo1 elongate compared with elo2 (which supplies C24 for ceramide), and is elo1 the S. pombe counterpart of budding-yeast ELO1 (C14->C16/C18), ELO2 or ELO3 in function despite its sequence-based name?
Experiment: Measure acyl-CoA/ceramide chain-length profiles in elo1 deletion, elo2 shut-off and double mutants, and assay elo1 in vitro (or by heterologous expression in elo2/elo3 budding-yeast mutants) for substrate specificity.
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)