Very-long-chain aldehyde decarbonylase that catalyzes the conversion of very-long-chain fatty aldehydes to alkanes through an oxidative decarbonylation reaction. Core component of the alkane biosynthetic pathway in cuticular wax formation, working in a multiprotein complex with CER3 and cytochrome b5 isoforms at the endoplasmic reticulum membrane. Specifically expressed in epidermis of aerial organs and essential for cuticle formation, drought tolerance, and pollen fertility.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005506 iron ion binding | IEA GO_REF:0000002 | ACCEPT | Summary: CER1 contains tripartite histidine-rich motifs (HX3H+HX2HH+HX2HH) that coordinate a di-iron catalytic center essential for aldehyde decarbonylase activity. The di-iron center is characteristic of the sterol desaturase family to which CER1 belongs. Reason: This annotation correctly captures CER1's iron ion binding through its conserved histidine-rich motifs that coordinate the di-iron active site. This is a core molecular function essential for catalytic activity. Supporting Evidence: PMID:22773744 Site-directed mutagenesis showed that CER1 His clusters are essential for alkane synthesis, whereas those of CER3 are not, suggesting that CYTB5s are specific CER1 cofactors file:ARATH/CER1/CER1-deep-research-falcon.md CER1 contains essential His-rich motifs consistent with a di-iron catalytic center file:ARATH/CER1/CER1-deep-research-falcon.md CER1 His→Ala mutants lose alkane synthesis but still interact with CER3, indicating these residues are catalytic rather than structural for complex assembly |
| GO:0005789 endoplasmic reticulum membrane | IEA GO_REF:0000044 | ACCEPT | Summary: CER1 is a multi-pass transmembrane protein localized to the endoplasmic reticulum membrane where cuticular wax biosynthesis occurs. This localization is essential for CER1 function in the alkane-forming pathway. Reason: Correct cellular localization. CER1 is an integral ER membrane protein and this is where it performs its aldehyde decarbonylase function as part of the wax biosynthesis machinery. Supporting Evidence: PMID:22773744 CER1 protein located to the endoplasmic reticulum ( ER ), where wax biosynthesis takes place file:ARATH/CER1/CER1-deep-research-falcon.md CER1 is experimentally supported to be **ER-localized**, colocalizing with CYTB5 isoforms at the ER, consistent with its role in wax precursor synthesis prior to export to the cuticle |
| GO:0008610 lipid biosynthetic process | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: Lipid biosynthetic process is a broad parent of the specific biological processes GO:0010025 (wax biosynthetic process) and GO:0043447 (alkane biosynthetic process), both already annotated with experimental evidence. Cuticular wax alkanes are surface lipids, so the term is not incorrect, but it is far less informative than the specific terms. Reason: Redundant generic parent of the specific and correctly supported biological process terms (wax/alkane biosynthetic process). Supporting Evidence: file:ARATH/CER1/CER1-deep-research-falcon.md CER1 functions in the conversion of **VLC aldehydes to VLC alkanes** (one carbon shorter), i.e., the **decarbonylation step** |
| GO:0016491 oxidoreductase activity | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: Oxidoreductase activity is a broad parent of the specific molecular function GO:0071771 (aldehyde oxygenase (deformylating) activity), which is already annotated. The CER1 reaction is redox-dependent and consumes NADPH and O2, so this term is not incorrect, but it is far less informative than the specific decarbonylase activity. Reason: Redundant generic parent of the specific and correct molecular function GO:0071771. The decarbonylation reaction is redox-coupled (NADPH/O2-dependent), but the specific term better captures the actual catalysis. Supporting Evidence: file:ARATH/CER1/CER1-deep-research-falcon.md coexpression of CYTB5 enhances alkane output in yeast—supporting CYTB5 as an **electron-transfer cofactor** for CER1 decarbonylation |
| GO:0016829 lyase activity | IEA GO_REF:0000043 | MARK AS OVER ANNOTATED | Summary: Lyase activity is a generic parent derived from the UniProt Lyase keyword (EC class 4). The specific molecular function GO:0071771 (aldehyde oxygenase (deformylating) activity, EC 4.1.99.5) is already annotated and is far more informative. Reason: Redundant generic parent of the specific and correct molecular function GO:0071771. Note that GO_REF:0000043 (SwissProt keyword mapping) annotations have been retired by GOA for cellular organisms; this term adds no specific information. |
| GO:0071771 aldehyde oxygenase (deformylating) activity | IEA GO_REF:0000120 | ACCEPT | Summary: This is the precise core molecular function of CER1. It catalyzes the oxidative decarbonylation of a very-long-chain fatty aldehyde to an alkane that is one carbon shorter, plus formate (EC 4.1.99.5; RHEA:21440), consistent with the UniProt catalytic activity record. This term is more informative than the generic parent terms GO:0016491 (oxidoreductase activity) and GO:0016829 (lyase activity) also present in GOA. Reason: Accurately captures the specific enzymatic reaction catalyzed by CER1 and represents its core molecular function. Strongly supported by genetic and yeast-reconstitution evidence. Supporting Evidence: file:ARATH/CER1/CER1-deep-research-falcon.md CER1 functions in the conversion of **VLC aldehydes to VLC alkanes** (one carbon shorter), i.e., the **decarbonylation step** file:ARATH/CER1/CER1-deep-research-falcon.md CER1 is best supported as the **catalytic decarbonylase** component of an ER-localized alkane-synthesis complex. |
| GO:0005515 protein binding | IPI PMID:38456566 The Arabidopsis cytochrome P450 enzyme CYP96A4 is involved i... | MARK AS OVER ANNOTATED | Summary: The generic protein binding term is uninformative. The IPI annotation cites an interaction with the wound-induced P450 CYP96A4 (AT5G52320); PMID:38456566 reports that CYP96A4 interacts with CER1 and CER3 and functions as a cofactor of the alkane synthesis complex. CER1's other documented interactions are with CER3 and with cytochrome b5 isoforms (CYTB5-B/-C/-D/-E) to form the very-long-chain alkane synthesis complex (PMID:22773744). All of these are heterocomplex/partner interactions rather than a defined informative molecular function, and the generic protein binding term does not capture the catalytic role; CER1's informative molecular function is already annotated as GO:0071771 (aldehyde oxygenase (deformylating) activity). Reason: The generic protein binding term is uninformative and over-annotated. The underlying IPI interaction (CER1-CYP96A4) and the documented CER1-CER3/CYTB5 complex interactions are heterocomplex associations, not a specific molecular function; CER1's informative molecular function is already captured by GO:0071771. UniProt also records CER1 as a homodimer (PMID:22773744), but no verbatim self-interaction evidence is available in the cached sources to justify proposing GO:0042803 here. Supporting Evidence: PMID:38456566 CYP96A4 interacted with CER1 and CER3, the core enzymes in the alkane-forming pathway associated with wax biosynthesis file:ARATH/CER1/CER1-deep-research-falcon.md CER1 physically interacts with CER3 and ER-localized cytochrome b5 isoforms; CER1/CER3 coexpression is mandatory for alkane production in yeast |
| GO:0009611 response to wounding | IEP PMID:38456566 The Arabidopsis cytochrome P450 enzyme CYP96A4 is involved i... | KEEP AS NON CORE | Summary: Manual review: response to wounding may be context-dependent or peripheral for CER1. Reason: Kept as non-core to preserve potentially valid context-specific annotation without elevating it to core function. Supporting Evidence: PMID:38456566 The Arabidopsis cytochrome P450 enzyme CYP96A4 is involved in the wound-induced biosynthesis of cuticular wax and cutin monomers. |
| GO:0009753 response to jasmonic acid | IEP PMID:38456566 The Arabidopsis cytochrome P450 enzyme CYP96A4 is involved i... | KEEP AS NON CORE | Summary: Manual review: response to jasmonic acid may be context-dependent or peripheral for CER1. Reason: Kept as non-core to preserve potentially valid context-specific annotation without elevating it to core function. Supporting Evidence: PMID:38456566 The Arabidopsis cytochrome P450 enzyme CYP96A4 is involved in the wound-induced biosynthesis of cuticular wax and cutin monomers. |
| GO:0160062 cutin-based cuticle development | IMP PMID:8718622 Molecular characterization of the CER1 gene of arabidopsis i... | KEEP AS NON CORE | Summary: CER1 contributes to the formation of the cuticle by supplying very-long-chain alkanes, the major wax component of the epicuticular layer. Loss of CER1 disrupts wax crystal deposition on aerial surfaces. CER1 acts in wax (alkane) biosynthesis rather than cutin polyester synthesis per se, so this broader cuticle-development term is retained as a valid but non-core developmental context. Reason: Cuticle development is a downstream developmental outcome of CER1-mediated wax alkane biosynthesis; retained as non-core context, as CER1's direct, core role is the enzymatic alkane biosynthesis step. Supporting Evidence: PMID:8718622 Molecular characterization of the CER1 gene of arabidopsis involved in epicuticular wax biosynthesis and pollen fertility. file:ARATH/CER1/CER1-deep-research-falcon.md cer1 mutants are wax-deficient/waxless, have strongly reduced or trace alkane levels, altered wax crystal deposition, increased aldehydes, and can show male sterility due to defective pollen coat formation |
| GO:0005739 mitochondrion | ISM GO_REF:0000122 | REMOVE | Summary: Mitochondrial localization is an automated sequence-model (ISM) prediction (AtSubP) that is contradicted by experimental evidence. CER1 is an integral endoplasmic reticulum membrane protein that colocalizes with cytochrome b5 isoforms at the ER, consistent with its role in wax precursor synthesis. Reason: Automated prediction contradicted by experimental ER localization (PMID:22773744). No evidence supports a mitochondrial role for CER1. Supporting Evidence: file:ARATH/CER1/CER1-deep-research-falcon.md CER1 is experimentally supported to be **ER-localized**, colocalizing with CYTB5 isoforms at the ER, consistent with its role in wax precursor synthesis prior to export to the cuticle |
| GO:0043447 alkane biosynthetic process | IDA PMID:22773744 Reconstitution of plant alkane biosynthesis in yeast demonst... | ACCEPT | Summary: Alkane biosynthetic process is the core biological process for CER1. As the aldehyde decarbonylase of the alkane-forming branch of cuticular wax biosynthesis, CER1 directly produces very-long-chain odd-chain alkanes (e.g., C29, C31, C33) one carbon shorter than the aldehyde precursor. This is supported by direct in vivo and yeast-reconstitution evidence (IDA, PMID:22773744). Reason: Core biological process directly supported by experimental evidence; represents the central physiological role of CER1. Supporting Evidence: PMID:22773744 Reconstitution of plant alkane biosynthesis in yeast demonstrates that Arabidopsis ECERIFERUM1 and ECERIFERUM3 are core components of a very-long-chain alkane synthesis complex. file:ARATH/CER1/CER1-deep-research-falcon.md CER1 is best supported as the **catalytic decarbonylase** component of an ER-localized alkane-synthesis complex. |
| GO:0009414 response to water deprivation | IMP PMID:21386033 Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-... | KEEP AS NON CORE | Summary: Manual review: response to water deprivation may be context-dependent or peripheral for CER1. Reason: Kept as non-core to preserve potentially valid context-specific annotation without elevating it to core function. Supporting Evidence: PMID:21386033 Mar 8. Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-long-chain alkane biosynthesis and influences plant response to biotic and abiotic stresses. |
| GO:0042742 defense response to bacterium | IMP PMID:21386033 Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-... | KEEP AS NON CORE | Summary: Manual review: defense response to bacterium may be context-dependent or peripheral for CER1. Reason: Kept as non-core to preserve potentially valid context-specific annotation without elevating it to core function. Supporting Evidence: PMID:21386033 Mar 8. Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-long-chain alkane biosynthesis and influences plant response to biotic and abiotic stresses. |
| GO:0043447 alkane biosynthetic process | IMP PMID:21386033 Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-... | ACCEPT | Summary: Alkane biosynthetic process is the core biological process for CER1. Overexpression of CER1 promotes very-long-chain alkane accumulation, while loss-of-function abolishes stem alkanes, confirming CER1 as the rate-determining enzyme of the alkane-forming branch (IMP, PMID:21386033). This is a second experimental annotation to the same core process term. Reason: Core biological process supported by overexpression and mutant phenotype evidence; the central physiological role of CER1. Supporting Evidence: PMID:21386033 Mar 8. Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-long-chain alkane biosynthesis and influences plant response to biotic and abiotic stresses. file:ARATH/CER1/CER1-deep-research-falcon.md CER1 functions in the conversion of **VLC aldehydes to VLC alkanes** (one carbon shorter), i.e., the **decarbonylation step** |
| GO:0050832 defense response to fungus | IMP PMID:21386033 Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-... | KEEP AS NON CORE | Summary: Manual review: defense response to fungus may be context-dependent or peripheral for CER1. Reason: Kept as non-core to preserve potentially valid context-specific annotation without elevating it to core function. Supporting Evidence: PMID:21386033 Mar 8. Overexpression of Arabidopsis ECERIFERUM1 promotes wax very-long-chain alkane biosynthesis and influences plant response to biotic and abiotic stresses. |
| GO:0010025 wax biosynthetic process | IMP PMID:8718622 Molecular characterization of the CER1 gene of arabidopsis i... | ACCEPT | Summary: Wax biosynthetic process is a core biological process for CER1. cer1 loss-of-function mutants are wax-deficient with disappearance of epicuticular wax crystals and strongly reduced very-long-chain alkanes, demonstrating CER1's essential role in cuticular wax production (IMP, PMID:8718622). Reason: Core biological process supported by mutant phenotype evidence; CER1 is essential for cuticular wax (alkane) production. Supporting Evidence: PMID:8718622 Molecular characterization of the CER1 gene of arabidopsis involved in epicuticular wax biosynthesis and pollen fertility. file:ARATH/CER1/CER1-deep-research-falcon.md cer1 mutants are wax-deficient/waxless, have strongly reduced or trace alkane levels, altered wax crystal deposition, increased aldehydes, and can show male sterility due to defective pollen coat formation |
| GO:0010025 wax biosynthetic process | IMP PMID:1847001 Chrysotile asbestos and health in Zimbabwe: I. Analysis of m... | REMOVE | Summary: This annotation duplicates the wax biosynthetic process annotation (above) but cites PMID:1847001, which is an unrelated publication about chrysotile asbestos and health in Zimbabwe. This is a mislabeled/erroneous reference in the source GOA (TAIR) and the cited paper provides no support for any CER1 function. The underlying GO term (wax biosynthetic process) is itself correct for CER1 and is already accepted via the properly referenced PMID:8718622 annotation. Reason: The cached record for PMID:1847001 is explicitly an asbestos epidemiology paper ("Chrysotile asbestos and health in Zimbabwe..."), which cannot support any Arabidopsis CER1 annotation - the row carries a wrong identifier (a mis-mapped PMID in the source database), a case where the mismatch is explicit in the cached record rather than inferred. The wax biosynthetic process term itself is correct for CER1 and remains accepted via the properly referenced PMID:8718622 row, so removing this mis-referenced duplicate loses no biology; the reference error should also be corrected at source. |
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