DCT-1 (DAF-16/FOXO controlled germline tumor affecting-1) is the C. elegans ortholog of mammalian BNIP3/NIX, functioning as an outer mitochondrial membrane (OMM) mitophagy receptor. DCT-1 contains a C-terminal transmembrane domain for OMM localization and a conserved WXXL LIR (LC3-interacting region)-like motif that enables direct binding to LGG-1/Atg8 to recruit autophagosomes to mitochondria. DCT-1 operates in a genetic pathway with PINK-1 and PDR-1/Parkin; under oxidative stress, DCT-1 is ubiquitinated at Lys-26 in a PINK-1-dependent manner. DCT-1 is transcriptionally regulated by DAF-16/FOXO and SKN-1/Nrf2, forming a homeostatic feedback loop that coordinates mitophagy with mitochondrial biogenesis. Loss of dct-1 leads to accumulation of dysfunctional mitochondria, increased ROS, decreased ATP, and shortened lifespan in long-lived mutants. DCT-1 also has ancestral roles in apoptosis, interacting with CED-3 and CED-9, though killing occurs through a BH3- and caspase-independent mechanism.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0043067 regulation of programmed cell death | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA annotation inferred from phylogenetic analysis. DCT-1/ceBNIP3 has documented roles in programmed cell death pathways. Early studies showed DCT-1 interacts with CED-9 (Bcl-2 homolog) and CED-3 (caspase) and can initiate apoptosis when overexpressed in mammalian cells (PMID:11114722, PMID:9824163). However, DCT-1 kills through a BH3- and caspase-independent mechanism, and the primary physiological function in C. elegans is mitophagy rather than apoptosis. Reason: While DCT-1 has ancestral apoptosis-related functions inherited from the BNIP3 family, the primary characterized function in C. elegans is as a mitophagy receptor. The apoptotic function appears to be a secondary/ancestral role. IBA annotation is phylogenetically appropriate but represents a non-core function. Supporting Evidence: PMID:11114722 ceBNIP3 protein interacts with CED-9 and BCL-XL, but unlike other pro-apoptotic BCL-2 family members, the BH3-like domain does not participate in dimerization file:worm/dct-1/dct-1-deep-research-falcon.md [DCT-1 has ancestral apoptosis-related functions from BNIP3 family, but primary characterized function is mitophagy] |
| GO:0005741 mitochondrial outer membrane | IBA GO_REF:0000033 | ACCEPT | Summary: IBA annotation for mitochondrial outer membrane localization. This is strongly supported by direct experimental evidence in C. elegans. DCT-1 contains a C-terminal transmembrane domain that mediates OMM localization (PMID:25896323, PMID:11114722). Reason: Core cellular localization for DCT-1 function as a mitophagy receptor. The IBA is consistent with direct IDA evidence showing DCT-1 localizes to mitochondria via its transmembrane domain. Supporting Evidence: PMID:11114722 Like BNIP3, the TM domain of ceBNIP3 mediates the localization of the protein to mitochondria and is also necessary for homodimerization and cell death in mammalian cells file:worm/dct-1/dct-1-deep-research-falcon.md DCT-1 is an integral OMM protein [mitochondrial outer membrane] |
| GO:0005634 nucleus | IBA GO_REF:0000033 | UNDECIDED | Summary: IBA annotation for nuclear localization. No direct experimental evidence for nuclear localization of DCT-1 in C. elegans was found in the literature reviewed. The primary localization is to the mitochondrial outer membrane. Some BNIP3 family members in mammals can localize to the nucleus, but this may not apply to DCT-1. Reason: The IBA inference is based on mammalian BNIP3/NIX data where some nuclear localization has been reported. However, all C. elegans experimental data describes mitochondrial localization. Without direct evidence in C. elegans, this annotation cannot be confidently accepted or rejected. |
| GO:0097345 mitochondrial outer membrane permeabilization | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: IBA annotation for mitochondrial outer membrane permeabilization (MOMP). BNIP3 family members in mammals can induce MOMP during apoptosis. DCT-1 in C. elegans interacts with CED-9/Bcl-2 and may influence mitochondrial membrane integrity, but its primary function is in mitophagy rather than MOMP-mediated apoptosis. Reason: While BNIP3 family proteins can influence MOMP, DCT-1's primary function in C. elegans is as a mitophagy receptor. The MOMP-related function may be an ancestral property but is not the core characterized function. DCT-1 kills through a BH3- and caspase-independent mechanism (PMID:11114722), suggesting the mechanism differs from classical MOMP. Supporting Evidence: PMID:11114722 ceBNIP3 kills mammalian cells by a caspase-independent mechanism. In conclusion, we find that although ceBNIP3 interacts with CED-9 and CED-3 it kills by a BH3- and caspase-independent mechanism |
| GO:0005739 mitochondrion | IEA GO_REF:0000117 | ACCEPT | Summary: IEA annotation from ARBA machine learning. DCT-1 is localized to mitochondria, specifically the outer membrane. This is a broad but correct annotation. Reason: Correct general localization. The more specific term (mitochondrial outer membrane, GO:0005741) is also annotated with experimental evidence, so this broader IEA annotation is acceptable as a parent term annotation. Supporting Evidence: PMID:11114722 the TM domain of ceBNIP3 mediates the localization of the protein to mitochondria |
| GO:0005740 mitochondrial envelope | IEA GO_REF:0000002 | ACCEPT | Summary: IEA annotation from InterPro BNIP3 domain mapping. DCT-1 localizes to the mitochondrial outer membrane, which is part of the mitochondrial envelope. Reason: Correct annotation at appropriate specificity. The mitochondrial envelope includes the outer membrane where DCT-1 is localized. This is consistent with experimental data. Supporting Evidence: PMID:11114722 the TM domain of ceBNIP3 mediates the localization of the protein to mitochondria |
| GO:0005741 mitochondrial outer membrane | IEA GO_REF:0000044 | ACCEPT | Summary: IEA annotation from UniProt subcellular location vocabulary mapping. DCT-1 is localized to the mitochondrial outer membrane as confirmed by direct experimental evidence. Reason: Correct annotation supported by direct experimental evidence (IDA from PMID:25896323). The IEA is redundant with the IDA but correctly captures the localization. Supporting Evidence: PMID:11114722 Like BNIP3, the TM domain of ceBNIP3 mediates the localization of the protein to mitochondria |
| GO:0006914 autophagy | IEA GO_REF:0000043 | ACCEPT | Summary: IEA annotation from UniProt keyword mapping (Autophagy keyword). DCT-1 is involved in mitophagy, which is a specific form of autophagy. This is a correct but broad annotation. Reason: Correct annotation. Mitophagy (GO:0000423) is a subtype of autophagy, so the parent term annotation is valid. DCT-1 is a key mediator of mitophagy as demonstrated in PMID:25896323. Supporting Evidence: PMID:25896323 We find that DCT-1 is a key mediator of mitophagy and longevity assurance under conditions of stress in C. elegans |
| GO:0006915 apoptotic process | IEA GO_REF:0000043 | KEEP AS NON CORE | Summary: IEA annotation from UniProt keyword mapping (Apoptosis keyword). DCT-1 has ancestral roles in apoptosis inherited from the BNIP3 family, interacting with CED-3 and CED-9. However, this is not the primary function in C. elegans. Reason: DCT-1 has documented interactions with apoptosis machinery (CED-3, CED-9) and can induce cell death when overexpressed, but kills through a BH3- and caspase-independent mechanism. The primary physiological function is mitophagy. This annotation reflects an ancestral/secondary function. Supporting Evidence: PMID:11114722 although ceBNIP3 interacts with CED-9 and CED-3 it kills by a BH3- and caspase-independent mechanism |
| GO:0016020 membrane | IEA GO_REF:0000002 | ACCEPT | Summary: IEA annotation from InterPro domain mapping. DCT-1 is a membrane protein localized to the mitochondrial outer membrane. Reason: Correct but very broad annotation. DCT-1 contains a transmembrane domain and is an integral membrane protein. More specific annotations (mitochondrial outer membrane) are also present. Supporting Evidence: PMID:11114722 ceBNIP3 contains a C-terminal transmembrane (TM) domain, a conserved domain (CD) of 19 amino acids, a BCL-2 homology-3 (BH3)-like domain and a PEST sequence |
| GO:0042802 identical protein binding | IEA GO_REF:0000117 | MODIFY | Summary: IEA annotation from ARBA machine learning. DCT-1 forms homodimers, so this annotation is correct and consistent with experimental evidence. Reason: The annotation is correct - DCT-1 homodimerizes - but the term "identical protein binding" is too general. The more specific term "protein homodimerization activity" (GO:0042803) is already annotated with IDA evidence. This IEA should be replaced with the more specific term. Proposed replacements: protein homodimerization activity Supporting Evidence: PMID:11114722 ceBNIP3 is expressed primarily as a 25 kDa monomer and a 50 kDa homodimer |
| GO:0043065 positive regulation of apoptotic process | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: IEA annotation from InterPro BNIP3 domain mapping. BNIP3 family proteins are typically pro-apoptotic. DCT-1 can induce cell death when overexpressed in mammalian cells, but this is not its primary physiological function in C. elegans. Reason: DCT-1 has pro-apoptotic activity when overexpressed, consistent with BNIP3 family function, but kills through a BH3- and caspase-independent mechanism. The primary in vivo function in C. elegans is mitophagy rather than apoptosis regulation. This is an ancestral/secondary function. Supporting Evidence: PMID:9824163 ceBNIP3 may be a novel component of the C. elegans apoptosis paradigm and may initiate apoptosis by recruiting CED-3 to mitochondria and other cytoplasmic membranes |
| GO:0000423 mitophagy | IMP PMID:25896323 Coordination of mitophagy and mitochondrial biogenesis durin... | ACCEPT | Summary: IMP annotation for mitophagy from Palikaras et al. 2015 (Nature). This is the core function of DCT-1 as a mitophagy receptor. Loss of dct-1 impairs mitophagy and leads to accumulation of dysfunctional mitochondria. Reason: Core biological process annotation. DCT-1 is required for the induction of mitophagy under stress conditions. This is the primary characterized function of DCT-1 in C. elegans, supported by extensive experimental evidence. Supporting Evidence: PMID:25896323 We find that DCT-1 is a key mediator of mitophagy and longevity assurance under conditions of stress in C. elegans. Impairment of mitophagy compromises stress resistance file:worm/dct-1/dct-1-deep-research-falcon.md DCT-1 is required for the induction of mitophagy under stress conditions |
| GO:0051726 regulation of cell cycle | IGI PMID:17934462 DAF-16/FOXO targets genes that regulate tumor growth in Caen... | KEEP AS NON CORE | Summary: IGI annotation from Pinkston-Gosse & Kenyon 2007 study on DAF-16 targets that regulate tumor growth. dct-1 is a DAF-16 target that affects germline tumor growth, which involves cell cycle regulation. Reason: DCT-1 is a DAF-16 target gene that influences germline tumor growth, which can be interpreted as cell cycle regulation. However, this is an indirect effect related to its roles in mitophagy and stress response rather than direct cell cycle regulation. The primary function is mitophagy. Supporting Evidence: PMID:17934462 Twenty-nine of 734 genes tested influenced germline-tumor cell proliferation or p53-dependent apoptosis |
| GO:0005741 mitochondrial outer membrane | IDA PMID:25896323 Coordination of mitophagy and mitochondrial biogenesis durin... | ACCEPT | Summary: IDA annotation for mitochondrial outer membrane localization from Palikaras et al. 2015. This is direct experimental evidence showing DCT-1::GFP co-localizes with mitochondrial markers. Reason: Core cellular localization with direct experimental evidence. This is the primary site of DCT-1 function as a mitophagy receptor. Supporting Evidence: file:worm/dct-1/dct-1-deep-research-falcon.md DCT-1 is an integral OMM protein. In vivo imaging and protease protection assays show DCT-1::GFP co-localizes with mitochondrial markers PMID:25896323 Coordination of mitophagy and mitochondrial biogenesis during ageing in C. |
| GO:0002020 protease binding | IPI PMID:11114722 The C. elegans orthologue ceBNIP3 interacts with CED-9 and C... | ACCEPT | Summary: IPI annotation for protease binding based on interaction with CED-3 caspase. DCT-1 interacts with the CED-3 caspase prodomain. Reason: Valid annotation supported by experimental evidence. DCT-1 heterodimerizes with proCED-3 by direct binding via the prodomain. This interaction may contribute to DCT-1's effects on cell death, though DCT-1 kills through a caspase-independent mechanism. Supporting Evidence: PMID:11114722 ceBNIP3 interacts with CED-3 but co-expression of CED-3 and ceBNIP3 does not significantly enhance induction of cell death in the presence or absence of CED-4 PMID:9824163 CeBNIP3 also efficiently heterodimerizes with the cell death protease proCED-3 by direct binding via the prodomain |
| GO:0002020 protease binding | IPI PMID:9824163 Regulation of apoptosis by a Caenorhabditis elegans BNIP3 ho... | ACCEPT | Summary: IPI annotation for protease binding from Yasuda et al. 1998, based on interaction with CED-3 caspase. Reason: Valid annotation with experimental evidence. Duplicate of the PMID:11114722 annotation but from an independent study confirming CED-3 binding. Supporting Evidence: PMID:9824163 CeBNIP3 also efficiently heterodimerizes with the cell death protease proCED-3 by direct binding via the prodomain |
| GO:0005515 protein binding | IPI PMID:11114722 The C. elegans orthologue ceBNIP3 interacts with CED-9 and C... | MARK AS OVER ANNOTATED | Summary: IPI annotation for protein binding based on interaction with CED-9. DCT-1 interacts with CED-9 (Bcl-2 homolog) via its transmembrane domain. Reason: "Protein binding" is too general and uninformative. The specific interaction is with CED-9, a Bcl-2 family member. A more specific term should be used, though GO may lack a specific "Bcl-2 family protein binding" term. The interaction is real but the annotation term is not informative. Supporting Evidence: PMID:11114722 ceBNIP3 protein interacts with CED-9 and BCL-XL, but unlike other pro-apoptotic BCL-2 family members, the BH3-like domain does not participate in dimerization. The ceBNIP3 TM domain mediates interaction with both CED-9 and BCL-XL |
| GO:0005515 protein binding | IPI PMID:9824163 Regulation of apoptosis by a Caenorhabditis elegans BNIP3 ho... | MARK AS OVER ANNOTATED | Summary: IPI annotation for protein binding from Yasuda et al. 1998, based on interaction with CED-9. Reason: "Protein binding" is too general. The specific interaction is with CED-9. Duplicate annotation from a different publication, same issue with term specificity. Supporting Evidence: PMID:9824163 In transiently transfected mammalian cells, ceBNIP3 complexes with CED-9, the worm homolog of BCL-2 |
| GO:0006915 apoptotic process | IMP PMID:11114722 The C. elegans orthologue ceBNIP3 interacts with CED-9 and C... | KEEP AS NON CORE | Summary: IMP annotation for apoptotic process from Cizeau et al. 2000. DCT-1 overexpression in mammalian cells induces cell death, but through a BH3- and caspase-independent mechanism. Reason: DCT-1 can induce apoptosis when overexpressed, but this is not its primary physiological function in C. elegans. The primary function is mitophagy. Additionally, the mechanism is caspase-independent, which differs from canonical apoptosis. Supporting Evidence: PMID:11114722 ceBNIP3 kills mammalian cells by a caspase-independent mechanism |
| GO:0008340 determination of adult lifespan | IMP PMID:16380712 Identification of direct DAF-16 targets controlling longevit... | KEEP AS NON CORE | Summary: IMP annotation for lifespan determination from Oh et al. 2006. dct-1 is a direct DAF-16 target that affects lifespan. Reason: DCT-1 affects lifespan through its role in mitophagy. Loss of dct-1 shortens the extended lifespan of daf-2, isp-1, and clk-1 mutants. This is an important phenotype but represents a downstream consequence of DCT-1's core mitophagy function rather than a direct molecular function. Supporting Evidence: PMID:16380712 inactivation of more than half of these genes significantly altered DAF-16-dependent functions, including life span, fat storage and dauer formation |
| GO:0031966 mitochondrial membrane | IDA PMID:11114722 The C. elegans orthologue ceBNIP3 interacts with CED-9 and C... | ACCEPT | Summary: IDA annotation for mitochondrial membrane localization from Cizeau et al. 2000. DCT-1 localizes to mitochondrial membranes via its transmembrane domain. Reason: Correct localization annotation. The more specific term (mitochondrial outer membrane) is also annotated, but this annotation is valid for the evidence available in this earlier study. Supporting Evidence: PMID:11114722 the TM domain of ceBNIP3 mediates the localization of the protein to mitochondria |
| GO:0042803 protein homodimerization activity | IDA PMID:11114722 The C. elegans orthologue ceBNIP3 interacts with CED-9 and C... | ACCEPT | Summary: IDA annotation for protein homodimerization activity. DCT-1 forms homodimers via its transmembrane domain, detected as a 50 kDa species. Reason: Core molecular function with direct experimental evidence. DCT-1/ceBNIP3 forms homodimers, and this dimerization is mediated by the transmembrane domain. Supporting Evidence: PMID:11114722 ceBNIP3 is expressed primarily as a 25 kDa monomer and a 50 kDa homodimer |
| GO:0032991 protein-containing complex | IPI PMID:9824163 Regulation of apoptosis by a Caenorhabditis elegans BNIP3 ho... | ACCEPT | Summary: IPI annotation for protein-containing complex based on ternary complex formation with CED-9 and CED-3. Reason: Valid annotation. DCT-1 forms complexes with CED-9 and CED-3. While this may represent ancestral apoptosis-related function, the complex formation is experimentally demonstrated. Supporting Evidence: PMID:9824163 In cells coexpressing CED-9, ceBNIP3 and CED-3, all three proteins exist as a ternary complex suggesting that CED-9 may suppress cooperative apoptosis induced by CED-3 and ceBNIP3 by simultaneous complex formation with CED-3 and ceBNIP3 |
| GO:0140580 mitochondrion autophagosome adaptor activity | IDA PMID:25896323 Coordination of mitophagy and mitochondrial biogenesis durin... | NEW | Summary: DCT-1 functions as a mitophagy receptor that bridges mitochondria to autophagosomes. It contains a WXXL LIR-like motif that binds LGG-1/Atg8 to recruit autophagy machinery to mitochondria. Reason: This molecular function term precisely captures DCT-1's core function as a mitophagy receptor/adaptor. DCT-1 colocalizes with LGG-1/Atg8 and facilitates recruitment of the autophagy machinery to mitochondria via its LIR motif. This is the key molecular function enabling mitophagy. Supporting Evidence: file:worm/dct-1/dct-1-deep-research-falcon.md DCT-1 colocalizes with LGG-1/Atg8 and facilitates recruitment of the autophagy machinery to mitochondria, engaging receptor-mediated mitophagy similar to mammalian BNIP3/NIX PMID:25896323 Coordination of mitophagy and mitochondrial biogenesis during ageing in C. |
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Download this section (compressed HTML)Q: Does DCT-1 interact directly with LGG-1/Atg8 in C. elegans?
Q: What is the physiological significance of DCT-1's apoptotic function vs mitophagy function?
Experiment: Co-immunoprecipitation of DCT-1 and LGG-1 in C. elegans would directly demonstrate DCT-1-LGG-1 interaction in vivo.
Hypothesis: DCT-1 directly binds LGG-1/Atg8 via its WXXL LIR-like motif
Experiment: Structure-function analysis of DCT-1 WXXL motif in mitophagy. While mutation of the WXXL motif impairs stress resistance, direct demonstration that this is due to loss of LGG-1 binding would strengthen the mitophagy receptor function annotation.
Hypothesis: The WXXL motif is required for DCT-1-mediated mitophagy
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