lag1 (UniProt P78970) encodes one of the two ceramide synthase subunits of fission yeast (Lag1 and Lac1; TLC-domain sphinganine N-acyltransferases), which acylate sphingoid bases with very-long-chain acyl-CoA to make ceramide. Lac1 and Lag1 co-immunoprecipitate and co-localise at the ER but make different ceramide and complex sphingolipid species. Unlike lac1, lag1 deletion does not affect cell-size control.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005783 endoplasmic reticulum | EXP PMID:35008733 The Ceramide Synthase Subunit Lac1 Regulates Cell Growth and... | ACCEPT | Summary: Lac1 and Lag1 co-localise at the ER. Supporting Evidence: PMID:35008733 We showed that Lac1 and Lag1 co-immunoprecipitate and co-localize at the endoplasmic reticulum. |
| GO:0005783 endoplasmic reticulum | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | ACCEPT | Summary: ORFeome screen: ER. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins |
| GO:0005783 endoplasmic reticulum | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT inference of ER localisation for the ceramide synthase family; consistent with direct imaging of Lag1 in S. pombe. Reason: The IBA is corroborated by S. pombe-specific evidence, where tagged Lac1 and Lag1 co-localise completely with a luminal ER marker (PMID:35008733). Supporting Evidence: PMID:35008733 Lac1 and Lag1 co-localized completely with the ER marker (Figure 2B), confirming that ceramide synthase localizes at the ER in fission yeast. |
| GO:0005789 endoplasmic reticulum membrane | IEA GO_REF:0000044 | ACCEPT | Summary: ER membrane (UniProt subcellular-location mapping). Reason: UniProt places Lag1 in the ER membrane by similarity (ECO:0000250) and predicts seven helical transmembrane segments; Lag1 co-localises with an ER marker in S. pombe (PMID:35008733), so an integral ER-membrane location is well supported. Supporting Evidence: file:SCHPO/lag1/lag1-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane {ECO:0000250}; PMID:35008733 Lac1 and Lag1 co-localized completely with the ER marker (Figure 2B), confirming that ceramide synthase localizes at the ER in fission yeast. |
| GO:0005789 endoplasmic reticulum membrane | NAS GO_REF:0000051 | ACCEPT | Summary: ER membrane (PomBase keyword/author statement). Reason: UniProt places Lag1 in the ER membrane by similarity (ECO:0000250) and predicts seven helical transmembrane segments; Lag1 co-localises with an ER marker in S. pombe (PMID:35008733), so an integral ER-membrane location is well supported. Supporting Evidence: file:SCHPO/lag1/lag1-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane {ECO:0000250}; PMID:35008733 Lac1 and Lag1 co-localized completely with the ER marker (Figure 2B), confirming that ceramide synthase localizes at the ER in fission yeast. |
| GO:0016020 membrane | IEA GO_REF:0000002 | TOO GENERAL | Summary: Generic membrane; true but entailed by the ER membrane rows. Reason: Membrane is true but uninformative. Lag1 is a multi-pass TLC-domain protein (seven predicted helical transmembrane segments) whose ER membrane location is by similarity to yeast Lag1/Lac1, and an S. pombe study (PMID:35008733) co-localizes Lag1 with Lac1 at the ER. The more specific GO:0005789 endoplasmic reticulum membrane is asserted elsewhere in this review. Supporting Evidence: file:SCHPO/lag1/lag1-uniprot.txt SUBCELLULAR LOCATION: Endoplasmic reticulum membrane {ECO:0000250}; Multi-pass membrane protein {ECO:0000250}. file:SCHPO/lag1/lag1-uniprot.txt FT TRANSMEM 63..83 PMID:35008733 We showed that Lac1 and Lag1 co-immunoprecipitate and co-localize at the endoplasmic reticulum. |
| GO:0046513 ceramide biosynthetic process | EXP PMID:35008733 The Ceramide Synthase Subunit Lac1 Regulates Cell Growth and... | ACCEPT | Summary: Lac1 and Lag1 each make distinct ceramide species. Supporting Evidence: PMID:35008733 However, each protein generates different species of ceramides and complex sphingolipids. |
| GO:0046513 ceramide biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT inference of ceramide biosynthesis for the Lag1/Lac1 ceramide synthase family. Reason: Consistent with the S. pombe lipidomics in PMID:35008733, where Lac1 and Lag1 each generate distinct ceramide species; family membership (Lag1/Lac1-like, IPR016439) supports the inheritance. Supporting Evidence: PMID:35008733 However, each protein generates different species of ceramides and complex sphingolipids. file:SCHPO/lag1/lag1-uniprot.txt SIMILARITY: Belongs to the sphingosine N-acyltransferase family. |
| GO:0046513 ceramide biosynthetic process | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro (IPR016439 Lag1/Lac1-like) mapping to ceramide biosynthesis. Reason: The InterPro family membership is supported by the record, and the process is shown for S. pombe Lag1 by lipid analysis in PMID:35008733. Supporting Evidence: file:SCHPO/lag1/lag1-uniprot.txt InterPro; IPR016439; Lag1/Lac1-like. PMID:35008733 However, each protein generates different species of ceramides and complex sphingolipids. |
| GO:0050291 sphingosine N-acyltransferase activity | IBA GO_REF:0000033 | ACCEPT | Summary: Ceramide synthase (sphinganine N-acyltransferase) activity (PAINT/EC). Reason: UniProt's catalytic-activity annotation (RHEA:23768) and family membership support the PAINT inference; PMID:35008733 identifies Lac1 and Lag1 as the S. pombe ceramide synthase. The catalytic activity of Lag1 itself has not been assayed in vitro in S. pombe; the budding-yeast orthologs are the experimental basis. Supporting Evidence: file:SCHPO/lag1/lag1-uniprot.txt Reaction=sphing-4-enine + a fatty acyl-CoA = an N-acylsphing-4-enine + PMID:35008733 Fission yeast Schizosaccharomyces pombe ceramide synthase is also encoded by the homologs Lac1 and Lag1. |
| GO:0050291 sphingosine N-acyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Ceramide synthase (sphinganine N-acyltransferase) activity (InterPro/EC mapping). Reason: UniProt's catalytic-activity annotation (RHEA:23768) and family membership support the mapping; PMID:35008733 identifies Lac1 and Lag1 as the S. pombe ceramide synthase. The catalytic activity of Lag1 itself has not been assayed in vitro in S. pombe. Supporting Evidence: file:SCHPO/lag1/lag1-uniprot.txt SIMILARITY: Belongs to the sphingosine N-acyltransferase family. PMID:35008733 Fission yeast Schizosaccharomyces pombe ceramide synthase is also encoded by the homologs Lac1 and Lag1. |
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)