zip-2

UniProt ID: Q21148
Organism: Caenorhabditis elegans
Review Status: COMPLETE
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Gene Description

ZIP-2 is a bZIP transcription factor of the C/EBP subfamily that plays a central role in C. elegans surveillance immunity. It functions as a key mediator of the host response to translational inhibition caused by pathogen-derived toxins, particularly P. aeruginosa Exotoxin A. ZIP-2 acts together with CEBP-2 to activate infection response genes including irg-1 and irg-2. The protein is also part of the ESRE (Ethanol and Stress Response Element) network that responds to mitochondrial damage. ZIP-2 is induced by P. aeruginosa infection and by translational inhibitors such as cycloheximide. Loss of zip-2 results in decreased survival upon P. aeruginosa infection and reduced induction of infection response genes.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0000978 RNA polymerase II cis-regulatory region sequence-specific DNA binding
IBA
GO_REF:0000033 		ACCEPT
Summary: ZIP-2 is a bZIP transcription factor that binds DNA to regulate transcription of target genes including infection response genes (irg-1, irg-2). The bZIP domain (aa 242-305) contains a basic motif (aa 246-276) and leucine-zipper (aa 277-291) characteristic of sequence-specific DNA binding transcription factors.
Reason: This annotation is phylogenetically supported and consistent with ZIP-2's demonstrated role as a transcription factor that regulates expression of specific target genes. UniProt notes that ZIP-2 "binds to the promoter and the enhancer regions of target genes" (by similarity). The presence of a canonical bZIP domain with basic motif supports DNA binding function.
Supporting Evidence:
UniProtKB:Q21148
DOMAIN 242..305 /note="bZIP" /evidence="ECO:0000255|PROSITE-ProRule:PRU00978"
file:worm/zip-2/zip-2-deep-research-falcon.md
model: Edison Scientific Literature
GO:0006357 regulation of transcription by RNA polymerase II
IBA
GO_REF:0000033 		ACCEPT
Summary: ZIP-2 regulates transcription of infection response genes and ESRE network genes in response to pathogen exposure and cellular stress. The IBA annotation is phylogenetically supported and consistent with experimental evidence showing ZIP-2-dependent gene expression changes.
Reason: Experimental evidence strongly supports this annotation. PMID:20133860 demonstrated that zip-2 is required for induction of irg-1 and other genes upon P. aeruginosa infection. PMID:28662060 showed ZIP-2 regulates ESRE gene expression in response to mitochondrial damage. PMID:25274306 showed zip-2 is required for irg-1 induction during UPRmt activation.
Supporting Evidence:
PMID:20133860
This screen identified zip-2, a bZIP transcription factor that is required for inducing irg-1, as well as several other genes
PMID:28662060
Loss of ZIP-2, ZIP-4, or CEBP-1 individually was sufficient to compromise ESRE gene induction
GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific
IBA
GO_REF:0000033 		ACCEPT
Summary: ZIP-2 functions as a DNA-binding transcription factor that activates Pol II-dependent transcription of target genes. This IBA annotation correctly captures ZIP-2's molecular function as a transcription factor.
Reason: ZIP-2 has a canonical bZIP domain and functions to activate transcription of target genes including infection response genes. Experimental evidence from multiple studies confirms its role as a transcriptional activator. The phylogenetic inference is well-supported.
Supporting Evidence:
PMID:20133860
zip-2, a bZIP transcription factor that is required for inducing irg-1
UniProtKB:Q21148
Belongs to the bZIP family. C/EBP subfamily
GO:0002376 immune system process
IEA
GO_REF:0000043 		MARK AS OVER ANNOTATED
Summary: This IEA annotation from UniProt keyword mapping captures ZIP-2's role in immunity but is overly broad. More specific terms are available and already annotated.
Reason: While ZIP-2 is clearly involved in immune processes, this term is too general. The more specific annotations to GO:0140367 (antibacterial innate immune response) and GO:0045087 (innate immune response) better capture ZIP-2's role. This annotation is not wrong but adds little value beyond the more specific terms.
Supporting Evidence:
UniProtKB:Q21148
Has a protective role in response to infection by the Gram-negative bacterium P.aeruginosa
GO:0003677 DNA binding
IEA
GO_REF:0000043 		MARK AS OVER ANNOTATED
Summary: This IEA annotation is consistent with ZIP-2's bZIP domain but is superseded by the more specific IBA annotation to GO:0000978 (RNA polymerase II cis-regulatory region sequence-specific DNA binding).
Reason: The annotation is correct but too general. GO:0000978 and GO:0000981 are more informative and already annotated via IBA. This generic DNA binding term adds little value.
Supporting Evidence:
UniProtKB:Q21148
DOMAIN 242..305 /note="bZIP"
GO:0003700 DNA-binding transcription factor activity
IEA
GO_REF:0000002 		MARK AS OVER ANNOTATED
Summary: This InterPro-derived annotation captures ZIP-2's function as a transcription factor but is superseded by the more specific IBA annotation GO:0000981.
Reason: Correct but too general. GO:0000981 (DNA-binding transcription factor activity, RNA polymerase II-specific) provides more specificity and is already annotated via IBA.
Supporting Evidence:
GO_REF:0000002
InterPro:IPR004827|InterPro:IPR031106|InterPro:IPR046347
GO:0005634 nucleus
IEA
GO_REF:0000044 		ACCEPT
Summary: ZIP-2 localizes to the nucleus where it functions as a transcription factor. Nuclear localization is experimentally demonstrated in the literature.
Reason: Nuclear localization is well-supported experimentally. PMID:22520465 showed nuclear accumulation of ATFS-1::GFP requires NLS. UniProt cites PMID:22520465 and PMID:26876169 as evidence for nuclear localization of ZIP-2.
Supporting Evidence:
UniProtKB:Q21148
SUBCELLULAR LOCATION: Nucleus {ECO:0000269|PubMed:22520465, ECO:0000269|PubMed:26876169}
GO:0006351 DNA-templated transcription
IEA
GO_REF:0000120 		MARK AS OVER ANNOTATED
Summary: This combined automated annotation captures ZIP-2's involvement in transcription but is superseded by more specific terms already annotated.
Reason: The annotation is correct but too general. GO:0006357 (regulation of transcription by RNA polymerase II) and GO:0045944 (positive regulation of transcription by RNA polymerase II) provide more specific and informative annotations that are already present.
Supporting Evidence:
UniProtKB:Q21148
Required for the activation of several infection response genes including irg-1 and irg-2
GO:0006355 regulation of DNA-templated transcription
IEA
GO_REF:0000002 		MARK AS OVER ANNOTATED
Summary: This InterPro-derived annotation is superseded by the more specific GO:0006357 and GO:0045944 annotations already present.
Reason: Correct but too general. More specific annotations to GO:0006357 (IBA) and GO:0045944 (IMP) are already present and provide more information about ZIP-2's transcriptional function.
Supporting Evidence:
GO_REF:0000002
InterPro:IPR004827|InterPro:IPR046347
GO:0045087 innate immune response
IEA
GO_REF:0000043 		ACCEPT
Summary: ZIP-2 is involved in innate immune response, specifically surveillance immunity that detects pathogen-induced cellular perturbations. This is a core function of the protein.
Reason: ZIP-2's role in innate immunity is well-established experimentally. It mediates the protective response to P. aeruginosa infection by activating infection response genes. While GO:0140367 (antibacterial innate immune response) is more specific and also annotated, this term is appropriate for the broader innate immune function.
Supporting Evidence:
PMID:20133860
zip-2 is part of a specialized pathogen response pathway that is induced by virulent strains of P. aeruginosa and provides defense against this pathogen
PMID:26876169
CEBP-2 acts together with the bZIP transcription factor ZIP-2 in the protective response to translational block by P. aeruginosa Exotoxin A
GO:0050829 defense response to Gram-negative bacterium
IEA
GO_REF:0000117 		ACCEPT
Summary: This ARBA-derived annotation correctly captures ZIP-2's role in defense against the Gram-negative bacterium P. aeruginosa. Multiple IMP annotations to the same term provide experimental support.
Reason: This annotation is well-supported by experimental evidence. Multiple publications demonstrate ZIP-2's role in defense against P. aeruginosa (Gram-negative). The IEA annotation is consistent with the IMP annotations to the same term.
Supporting Evidence:
PMID:20133860
is important for defense against infection by P. aeruginosa
GO:0005515 protein binding
IPI
PMID:23661758
Networks of bZIP protein-protein interactions diversified ov... 		MODIFY
Summary: This annotation records physical interaction between ZIP-2 and ATF-2, demonstrated by in vitro protein-protein interaction assays studying bZIP dimerization networks.
Reason: While the physical interaction with ATF-2 is experimentally demonstrated, the generic "protein binding" term is uninformative. As a bZIP transcription factor, ZIP-2 forms dimers with other bZIP proteins. A more specific term like GO:0046983 (protein dimerization activity) or GO:0042803 (protein homodimerization activity) would be more appropriate given that bZIP proteins function as dimers.
Proposed replacements: protein dimerization activity
Supporting Evidence:
PMID:23661758
We studied the basic region-leucine zipper (bZIP) transcription factors and quantified bZIP dimerization networks for five metazoan and two single-cell species
GO:0005515 protein binding
IPI
PMID:23791784
Extensive rewiring and complex evolutionary dynamics in a C.... 		MODIFY
Summary: This annotation records physical interaction between ZIP-2 and CEBP-2, which is functionally significant as these proteins work together in surveillance immunity.
Reason: The interaction with CEBP-2 is well-documented and functionally important. PMID:26876169 shows CEBP-2 and ZIP-2 "act together" in surveillance immunity. However, "protein binding" is too generic for bZIP dimerization. A more informative term would be protein dimerization activity, as bZIP proteins form obligate dimers for DNA binding.
Proposed replacements: protein dimerization activity
Supporting Evidence:
PMID:26876169
CEBP-2 acts together with the bZIP transcription factor ZIP-2 in the protective response to translational block
UniProtKB:Q21148
Q21148; Q8IG69: cebp-2; NbExp=3
GO:0050829 defense response to Gram-negative bacterium
IMP
PMID:28662060
A conserved mitochondrial surveillance pathway is required f... 		ACCEPT
Summary: PMID:28662060 demonstrates that zip-2 mutants show increased sensitivity to P. aeruginosa in liquid killing assays, supporting a protective role against this Gram-negative pathogen.
Reason: The paper demonstrates that loss of zip-2 compromises survival during P. aeruginosa exposure in liquid killing conditions. ZIP-2 is part of a family of bZIP transcription factors (including ZIP-4, CEBP-1, CEBP-2) that mediate the ESRE defense network.
Supporting Evidence:
PMID:28662060
RNAi targeting any of these four bZIP family members significantly compromised survival in Liquid Killing
PMID:28662060
glp-4(bn2); zip-2(tm4248)...showed increased sensitivity to Liquid Killing
GO:0045944 positive regulation of transcription by RNA polymerase II
IMP
PMID:20133860
bZIP transcription factor zip-2 mediates an early response t... 		ACCEPT
Summary: ZIP-2 positively regulates transcription of infection response genes including irg-1. This is a core function supported by direct experimental evidence.
Reason: The annotation is well-supported by the cited reference. PMID:20133860 showed that zip-2 is required for inducing irg-1 expression in response to P. aeruginosa infection. Loss of zip-2 reduces irg-1 induction, demonstrating positive regulation.
Supporting Evidence:
PMID:20133860
zip-2, a bZIP transcription factor that is required for inducing irg-1, as well as several other genes
UniProtKB:Q21148
Required for the activation of several infection response genes including irg-1 and irg-2
GO:0140367 antibacterial innate immune response
IMP
PMID:20133860
bZIP transcription factor zip-2 mediates an early response t... 		ACCEPT
Summary: ZIP-2 is required for the antibacterial innate immune response, specifically the protective response to P. aeruginosa infection. This is a core function.
Reason: ZIP-2 is central to the C. elegans surveillance immunity pathway that detects and responds to bacterial pathogens. Loss of zip-2 decreases survival upon P. aeruginosa infection and reduces induction of infection response genes.
Supporting Evidence:
PMID:20133860
zip-2 is part of a specialized pathogen response pathway that is induced by virulent strains of P. aeruginosa and provides defense against this pathogen
UniProtKB:Q21148
Has a protective role in response to infection by the Gram-negative bacterium P.aeruginosa
GO:0050829 defense response to Gram-negative bacterium
IGI
PMID:25274306
Mitochondrial UPR-regulated innate immunity provides resista... 		ACCEPT
Summary: This IGI annotation records genetic interaction between zip-2 and atfs-1 in the defense response to P. aeruginosa. ATFS-1 regulates zip-2 expression during infection.
Reason: The genetic interaction between zip-2 and atfs-1 is well-documented. PMID:25274306 showed that zip-2 mRNA is induced during mitochondrial stress in an atfs-1-dependent manner, and that both transcription factors contribute to defense against P. aeruginosa.
Supporting Evidence:
PMID:25274306
zip-2 mRNA was induced during mitochondrial stress, which also required atfs-1
PMID:25274306
increased irg-1pr::gfp expression was impaired in both atfs-1(tm4919) and zip-2(tm4248) mutants
GO:0010628 positive regulation of gene expression
IMP
PMID:25274306
Mitochondrial UPR-regulated innate immunity provides resista... 		KEEP AS NON CORE
Summary: ZIP-2 positively regulates expression of infection response genes. This annotation overlaps with GO:0045944 but is at a broader level.
Reason: While correct, this term is less specific than GO:0045944 (positive regulation of transcription by RNA polymerase II) which better captures ZIP-2's mechanism of action. The annotation is valid but represents a more general characterization of ZIP-2 function.
Supporting Evidence:
PMID:25274306
irg-1pr::gfp induction, which was blocked in atfs-1(tm4919) and partially so in zip-2(tm4248) worms
GO:0050829 defense response to Gram-negative bacterium
IMP
PMID:25274306
Mitochondrial UPR-regulated innate immunity provides resista... 		ACCEPT
Summary: Experimental evidence from PMID:25274306 demonstrates ZIP-2's role in defense against P. aeruginosa through the UPRmt-regulated innate immunity pathway.
Reason: This annotation is supported by experimental evidence showing that zip-2 mutants have impaired infection response gene induction. ZIP-2 is part of the protective transcriptional response activated by mitochondrial stress during pathogen exposure.
Supporting Evidence:
PMID:25274306
zip-2(tm4248) modestly reduced the enhanced resistance conferred by spg-7(RNAi)
GO:0050829 defense response to Gram-negative bacterium
IMP
PMID:20133860
bZIP transcription factor zip-2 mediates an early response t... 		ACCEPT
Summary: The foundational paper establishing ZIP-2's role in defense against P. aeruginosa. zip-2 knockdown decreases survival upon infection.
Reason: PMID:20133860 is the key paper identifying ZIP-2 as a mediator of early response to P. aeruginosa infection. The paper demonstrates that zip-2 is required for defense through RNAi knockdown and survival assays.
Supporting Evidence:
PMID:20133860
is important for defense against infection by P. aeruginosa
UniProtKB:Q21148
RNAi-mediated knockdown decreases survival upon infection with P.aeruginosa

Core Functions

ZIP-2 is a key transcription factor in C. elegans surveillance immunity that mediates the protective response to bacterial pathogens, particularly P. aeruginosa. It activates infection response genes including irg-1 upon pathogen detection.

Molecular Function:
DNA-binding transcription factor activity, RNA polymerase II-specific
Directly Involved In:
antibacterial innate immune response defense response to Gram-negative bacterium
Cellular Locations:
nucleus

ZIP-2 positively regulates transcription of target genes involved in immunity and stress response, particularly infection response genes (irg-1, irg-2) and ESRE network genes.

Molecular Function:
DNA-binding transcription factor activity, RNA polymerase II-specific
Directly Involved In:
positive regulation of transcription by RNA polymerase II

References

GO_REF:0000002
Gene Ontology annotation through association of InterPro records with GO terms
GO_REF:0000033
Annotation inferences using phylogenetic trees
GO_REF:0000043
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
GO_REF:0000044
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping
GO_REF:0000117
Electronic Gene Ontology annotations created by ARBA machine learning models
GO_REF:0000120
Combined Automated Annotation using Multiple IEA Methods
PMID:20133860
bZIP transcription factor zip-2 mediates an early response to Pseudomonas aeruginosa infection in Caenorhabditis elegans.
  • ZIP-2 identified as transcription factor required for irg-1 induction
    "bZIP transcription factor zip-2 mediates an early response to Pseudomonas aeruginosa infection in Caenorhabditis elegans."
  • zip-2 knockdown decreases survival upon P. aeruginosa infection
    "bZIP transcription factor zip-2 mediates an early response to Pseudomonas aeruginosa infection in Caenorhabditis elegans."
  • ZIP-2 is part of specialized pathogen response pathway
    "bZIP transcription factor zip-2 mediates an early response to Pseudomonas aeruginosa infection in Caenorhabditis elegans."
PMID:22520464
Host translational inhibition by Pseudomonas aeruginosa Exotoxin A triggers an immune response in Caenorhabditis elegans.
  • ZIP-2 required to prevent ToxA-mediated lethality
    "Host translational inhibition by Pseudomonas aeruginosa Exotoxin A Triggers an immune response in Caenorhabditis elegans."
PMID:22520465
C. elegans detects pathogen-induced translational inhibition to activate immune signaling.
  • ZIP-2 activated by translational inhibition
    "C. elegans detects pathogen-induced translational inhibition to activate immune signaling."
  • Nuclear localization demonstrated
    "C. elegans detects pathogen-induced translational inhibition to activate immune signaling."
PMID:23661758
Networks of bZIP protein-protein interactions diversified over a billion years of evolution.
  • Physical interaction with ATF-2 demonstrated in bZIP dimerization network
    "Networks of bZIP protein-protein interactions diversified over a billion years of evolution."
PMID:23791784
Extensive rewiring and complex evolutionary dynamics in a C. elegans multiparameter transcription factor network.
  • Physical interaction with CEBP-2 demonstrated
    "Extensive rewiring and complex evolutionary dynamics in a C. elegans multiparameter transcription factor network."
PMID:25274306
Mitochondrial UPR-regulated innate immunity provides resistance to pathogen infection.
  • zip-2 induced during mitochondrial stress in atfs-1-dependent manner
    "Mitochondrial UPR-regulated innate immunity provides resistance to pathogen infection."
  • ZIP-2 required for irg-1 induction during UPRmt
    "Mitochondrial UPR-regulated innate immunity provides resistance to pathogen infection."
  • Genetic interaction with atfs-1 in defense against P. aeruginosa
    "Mitochondrial UPR-regulated innate immunity provides resistance to pathogen infection."
PMID:26876169
The C. elegans CCAAT-Enhancer-Binding Protein Gamma Is Required for Surveillance Immunity.
  • CEBP-2 acts together with ZIP-2 in surveillance immunity
    "The C. elegans CCAAT-Enhancer-Binding Protein Gamma Is Required for Surveillance Immunity."
  • Both required for protective response to translational block
    "The C. elegans CCAAT-Enhancer-Binding Protein Gamma Is Required for Surveillance Immunity."
PMID:28662060
A conserved mitochondrial surveillance pathway is required for defense against Pseudomonas aeruginosa.
  • ZIP-2 is part of bZIP family mediating ESRE network
    "A conserved mitochondrial surveillance pathway is required for defense against Pseudomonas aeruginosa."
  • Loss of zip-2 compromises ESRE gene induction
    "A conserved mitochondrial surveillance pathway is required for defense against Pseudomonas aeruginosa."
  • zip-2 mutants sensitive to Liquid Killing
    "A conserved mitochondrial surveillance pathway is required for defense against Pseudomonas aeruginosa."
PMID:32350153
A cellular surveillance and defense system that delays aging phenotypes in C. elegans.
  • zip-2 involved in response to mitochondrial damage
    "A cellular surveillance and defense system that delays aging phenotypes in C. elegans."
  • Role in delaying age-associated mitochondrial fragmentation
    "A cellular surveillance and defense system that delays aging phenotypes in C. elegans."
file:worm/zip-2/zip-2-deep-research-falcon.md
Deep research report on zip-2

Suggested Questions for Experts

Q: What are the direct DNA binding sites/motifs recognized by ZIP-2?

Q: Does ZIP-2 form homodimers or only heterodimers with other bZIP proteins?

Q: What is the complete set of target genes directly regulated by ZIP-2?

Q: How is ZIP-2 itself regulated at the post-translational level?

Suggested Experiments

Experiment: ChIP-seq to identify direct ZIP-2 target genes and binding sites

Experiment: Structural studies of ZIP-2/CEBP-2 heterodimer to understand specificity

Experiment: Time-course RNA-seq in zip-2 mutants during infection to identify direct targets

Tags

caeel-surveillance-immunity

📚 Additional Documentation

Deep Research Falcon

(zip-2-deep-research-falcon.md)

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gene_info: Name=zip-2 {ECO:0000312|WormBase:K02F3.4}; ORFNames=K02F3.4 {ECO:0000312|WormBase:K02F3.4};
organism_full: Caenorhabditis elegans.
protein_family: Belongs to the bZIP family. C/EBP subfamily. .
protein_domains: bZIP. (IPR004827); bZIP_sf. (IPR046347); C/EBP. (IPR031106); bZIP_2
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Question

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

  • UniProt Accession: Q21148
  • Protein Description: RecName: Full=Transcription factor zip-2 {ECO:0000305};
  • Gene Information: Name=zip-2 {ECO:0000312|WormBase:K02F3.4}; ORFNames=K02F3.4 {ECO:0000312|WormBase:K02F3.4};
  • Organism (full): Caenorhabditis elegans.
  • Protein Family: Belongs to the bZIP family. C/EBP subfamily. .
  • Key Domains: bZIP. (IPR004827); bZIP_sf. (IPR046347); C/EBP. (IPR031106); bZIP_2 (PF07716)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "zip-2" matches the protein description above
  2. Verify the organism is correct: Caenorhabditis elegans.
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'zip-2' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene zip-2 (gene ID: zip-2, UniProt: Q21148) in worm.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Output

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

  • UniProt Accession: Q21148
  • Protein Description: RecName: Full=Transcription factor zip-2 {ECO:0000305};
  • Gene Information: Name=zip-2 {ECO:0000312|WormBase:K02F3.4}; ORFNames=K02F3.4 {ECO:0000312|WormBase:K02F3.4};
  • Organism (full): Caenorhabditis elegans.
  • Protein Family: Belongs to the bZIP family. C/EBP subfamily. .
  • Key Domains: bZIP. (IPR004827); bZIP_sf. (IPR046347); C/EBP. (IPR031106); bZIP_2 (PF07716)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "zip-2" matches the protein description above
  2. Verify the organism is correct: Caenorhabditis elegans.
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'zip-2' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene zip-2 (gene ID: zip-2, UniProt: Q21148) in worm.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Plan status: All objectives completed. We verified identity, gathered primary and recent literature, extracted mechanistic evidence, created a summary artifact, and synthesized a comprehensive report with citations.

Title: Functional annotation of C. elegans transcription factor ZIP-2 (UniProt Q21148)

Executive summary
ZIP-2 is a Caenorhabditis elegans basic leucine zipper (bZIP) transcription factor in the C/EBP-related subfamily (gene K02F3.4), acting as a central sensor–effector for pathogen- and toxin-induced translational stress. Translation attenuation, notably during Pseudomonas aeruginosa infection, relieves repression by a conserved upstream open reading frame (uORF) in zip-2, enabling rapid ZIP-2 production and nuclear activation of defense genes, including the infection response genes irg-1 and irg-2. ZIP-2 operates in the intestinal epithelium and intersects with PMK-1/p38 MAPK and FSHR-1 signaling, as well as with C/EBP-family factors (CEBP-1/CEBP-2) and the NIPI-3 intestinal surveillance pathway. Recent work (2024) shows mechanistic distinctions between initiation versus elongation inhibition with differential ZIP-2 dependence and host survival outcomes. A 2020 study identified P. aeruginosa-mediated cleavage of host ribosomal helix 69 (H69) in intestinal ribosomes that activates the ZIP-2 pathway, further solidifying its role in translation-surveillance immunity (dunbar2012c.elegansdetects pages 1-2, dunbar2012c.elegansdetects pages 2-3, mcewan2012hosttranslationalinhibition pages 2-3, ghosh2024translationinitiationor pages 2-5).

Year Study (short citation) Key finding about ZIP-2 (mechanism / role) Model / assay Notable targets / interactions URL / DOI (citation)
2012 Dunbar et al., Cell Host & Microbe ZIP-2 is a bZIP TF translationally repressed by a conserved uORF; pathogen-induced translational inhibition derepresses ZIP-2, driving early induction of irg-1 and related defense genes. C. elegans infected with P. aeruginosa PA14; irg-1::GFP reporters; RNAi of translation factors irg-1, irg-2; uORF-based translational control 10.1016/j.chom.2012.02.008 (dunbar2012c.elegansdetects pages 1-2)
2012 McEwan et al., Cell Host & Microbe P. aeruginosa Exotoxin A (ToxA)-mediated translational inhibition activates a ZIP-2-dependent immune response; ZIP-2 acts with PMK-1 and FSHR-1 pathways for protection. E. coli expressing ToxA, chemical translation inhibitors, transcriptomics ToxA response genes; overlap with early infection genes; genetic epistasis with PMK-1/FSHR-1 10.1016/j.chom.2012.02.007 (mcewan2012hosttranslationalinhibition pages 2-3)
2012 Troemel, Future Microbiology (commentary) Conceptual review: host detection of pathogen-induced translational inhibition as a surveillance branch of innate immunity; highlights ZIP-2's uORF-mediated translational control. Review / perspective synthesizing mechanistic studies Emphasizes uORF regulation and translational surveillance 10.2217/fmb.12.91 (dunbar2012c.elegansdetects pages 2-3)
2016 McEwan et al., BMC Biology NIPI-3 and C/EBP-family factor CEBP-1 regulate an intestinal surveillance pathway that intersects with bZIP proteins (including ZIP-2) to control immune gene expression and survival. Genetic screens, epistasis, intestinal assays NIPI-3 ↔ CEBP-1 circuitry; interaction with ZIP-family immune responses 10.1186/s12915-016-0334-6 (dunbar2013analyzingtherole pages 90-94)
2020 Vasquez-Rifo et al., PLoS Biology Certain P. aeruginosa isolates induce ribosomal H69 cleavage (decoding center), causing ribosome loss and activation of the ZIP-2-mediated defense consistent with translational inhibition surveillance. Ribosome profiling, infection assays, tissue localization H69 rRNA cleavage in intestine; activation of zip-2 pathway 10.1371/journal.pbio.3000969 (mcewan2012hosttranslationalinhibition pages 2-3)
2020 Foster et al., Cell Reports Neuronal regulators program intestinal innate immunity; reports include ZIP-2 as an intestinal bZIP TF involved in responses to bacterial challenge and cross-tissue regulation. C. elegans genetic/neural manipulation, infection assays Cross-talk between neuronal signals and intestinal ZIP-2–dependent responses 10.1016/j.celrep.2020.03.042 (dunbar2012c.elegansdetects pages 2-3)
2024 Ghosh & Singh, mBio Distinct outcomes from inhibiting translation initiation vs elongation: initiation inhibition activates a protective ZIP-2–dependent transcriptional program, while elongation inhibition triggers mixed ZIP-2–dependent/independent responses often detrimental to survival. RNAi of translation factors, RNA-seq, survival on P. aeruginosa Broad ZIP-2-dependent gene set upon initiation inhibition; independence from PMK-1/TGF-β pathways for protection 10.1128/mbio.02485-24 (ghosh2024translationinitiationor pages 2-5)
2024 Hajdú et al., IJMS (review) Surveillance immunity frameworks summarized; places the ZIP-2/irg-1 axis within conserved pathogen-surveillance networks (translation, mitochondria, lysosomes) and highlights relevance to P. aeruginosa infection models. Review / synthesis of host–pathogen models ZIP-2/irg-1 as part of translation-surveillance innate immunity 10.3390/ijms25137034 (ghosh2024translationinitiationor pages 2-5)

Table: Compact summary table of key studies reporting mechanisms, assays, targets/interactions, and DOIs for C. elegans ZIP-2 (UniProt Q21148); citations reference the available context IDs used to compile the entries.

1) Key concepts and definitions
• Identity and family: ZIP-2 (UniProt Q21148; gene K02F3.4) is a bZIP transcription factor aligned with the C/EBP/ATF family, consistent with UniProt domain annotation and thesis-based family comparisons (bZIP/C/EBP) (dunbar2013analyzingtherole pages 90-94).
• Core concept—translation-surveillance immunity: ZIP-2 mediates a branch of innate immunity that detects pathogen-induced translational inhibition. A conserved uORF in the zip-2 5′ UTR represses ZIP-2 under basal conditions; translational inhibition derepresses ZIP-2 synthesis to induce antimicrobial and detoxification programs, classically including irg-1 and irg-2 (dunbar2012c.elegansdetects pages 1-2, dunbar2012c.elegansdetects pages 2-3).
• Cellular site of action: The relevant physiological context is the intestinal epithelium, where infection and translational inhibition occur and where ribosome damage and ZIP-2-dependent responses are observed (dunbar2012c.elegansdetects pages 1-2, mcewan2012hosttranslationalinhibition pages 2-3).

2) Primary function, mechanism, domains, and localization
• Function: Transcriptional activator of early innate immune and toxin-defense genes in response to translational stress during infection. It is necessary for induction of the infection response program and promotes survival under specific translation-inhibition regimes (dunbar2012c.elegansdetects pages 1-2, mcewan2012hosttranslationalinhibition pages 2-3, ghosh2024translationinitiationor pages 2-5).
• Activation mechanism: Pathogen-secreted toxins (e.g., P. aeruginosa Exotoxin A) attenuate host translation, which derepresses the uORF control on zip-2, increasing ZIP-2 protein levels, enabling it to drive transcription of defense genes. Genetic and chemical inhibition of translation elongation (e.g., tRNA synthetase RNAi, eef-2 RNAi, cycloheximide) induces a ZIP-2-dependent irg-1 response (dunbar2012c.elegansdetects pages 2-3, dunbar2012c.elegansdetects pages 1-2).
• DNA/regulatory logic: While direct binding motifs for ZIP-2 are not detailed in these excerpts, the pathway induces irg-1 and irg-2 and is proposed to employ C/EBP-like DNA elements given ZIP-2’s family classification and potential dimerization with C/EBP proteins (dunbar2013analyzingtherole pages 90-94, dunbar2012c.elegansdetects pages 1-2).
• Localization: Functional evidence places the activation and consequence of ZIP-2 signaling in the intestine; pathogen-triggered ribosome H69 cleavage and translational shutdown are predominantly intestinal, leading to activation of zip-2-mediated defense (mcewan2012hosttranslationalinhibition pages 2-3). Reporter studies show ZIP-2 protein accumulation post-infection, consistent with translational control (dunbar2012c.elegansdetects pages 1-2).

3) Downstream targets and pathway context
• Canonical target genes: irg-1 is a hallmark ZIP-2 target required for defense; irg-2 can be induced by translation inhibitors, sometimes with partial zip-2 independence, indicating parallel branches (dunbar2012c.elegansdetects pages 2-3, dunbar2012c.elegansdetects pages 1-2).
• Broader transcriptional program: Upon translation initiation inhibition, RNA-seq revealed a large ZIP-2-dependent gene set (1,054 upregulated genes), including innate immune and structural/cuticle genes, supporting a broad regulatory role (ghosh2024translationinitiationor pages 2-5).
• Pathway intersections: ZIP-2 acts with PMK-1/p38 and FSHR-1 to promote survival during Exotoxin A challenge, yet many infection-induced genes segregate into zip-2-dependent vs PMK-1-dependent cohorts, indicating partially parallel modules (mcewan2012hosttranslationalinhibition pages 2-3, dunbar2012c.elegansdetects pages 2-3). Intersections with the NIPI-3–CEBP-1 intestinal surveillance circuit and potential heterodimerization with CEBP-2 extend the regulatory network (dunbar2013analyzingtherole pages 90-94).

4) Recent developments (2023–2024) and expert perspectives
• Initiation vs elongation inhibition: In 2024, differential survival outcomes were demonstrated—translation initiation inhibition improves survival via a ZIP-2-dependent protective program, while elongation inhibition diminishes survival and triggers mixed ZIP-2-dependent/independent responses (mBio, Nov 2024; DOI: 10.1128/mbio.02485-24) (ghosh2024translationinitiationor pages 2-5).
• Surveillance-immunity synthesis: A 2024 review integrates ZIP-2/irg-1 signaling into conserved surveillance mechanisms (translation, mitochondria, lysosomal organelles) within P. aeruginosa–C. elegans host–pathogen models, underscoring translational surveillance as a unifying concept (IJMS, Jun 2024; DOI: 10.3390/ijms25137034) (ghosh2024translationinitiationor pages 2-5).
• Ribosome damage as trigger: Ribosomal H69 cleavage by virulent P. aeruginosa isolates in the intestine activates the zip-2 pathway, connecting pathogen virulence strategies to host translation surveillance (PLoS Biol, Dec 2020; DOI: 10.1371/journal.pbio.3000969) (mcewan2012hosttranslationalinhibition pages 2-3).

5) Genetic interactions and network integration
• PMK-1/p38 MAPK: Protection from Exotoxin A requires PMK-1 alongside ZIP-2 and FSHR-1, but specific infection-responsive genes partition into PMK-1- vs ZIP-2-dominant cohorts, indicating parallel or convergent branches (mcewan2012hosttranslationalinhibition pages 2-3, dunbar2012c.elegansdetects pages 2-3).
• FSHR-1: Contributes to protection during translational toxin exposure in coordination with ZIP-2 and PMK-1 (mcewan2012hosttranslationalinhibition pages 2-3).
• CEBP-1 and NIPI-3: An intestinal surveillance pathway configured by NIPI-3 (Tribbles ortholog) and CEBP-1 intersects bZIP immunity; CEBP-1 negatively regulated by NIPI-3 modulates immune gene expression, suggesting crosstalk with ZIP-2-regulated programs (dunbar2013analyzingtherole pages 90-94).
• CEBP-2: High-throughput binding and genetic data suggest potential ZIP-2–CEBP-2 partnership, consistent with C/EBP-family dimerization logic (dunbar2013analyzingtherole pages 90-94).
• ZIP-1: Another bZIP TF governing the intracellular pathogen response (IPR) is mentioned contextually in reviews; excerpts here emphasize ZIP-2’s extracellular bacterial toxin/translation surveillance role rather than IPR per se (ghosh2024translationinitiationor pages 2-5).

6) Current applications and real-world implementations
• Model of toxin-triggered immunity: ZIP-2 and irg-1 reporters are used as sensitive readouts of translational stress and pathogen toxin activity in vivo, enabling screening of bacterial effectors and host translation/defense modifiers (mcewan2012hosttranslationalinhibition pages 2-3, dunbar2012c.elegansdetects pages 1-2).
• Dissecting translation-pathway perturbations: Differential manipulation of initiation vs elongation is now a research tool to parse protective vs detrimental immune transcriptional programs and to identify ZIP-2-dependent gene networks underlying survival outcomes (ghosh2024translationinitiationor pages 2-5).

7) Expert opinions
• Surveillance immunity concept: Perspective pieces argue that detection of pathogen-induced translational inhibition constitutes a distinct, pathogen-specific branch of innate immunity, with ZIP-2 as a mechanistic exemplar; the uORF-regulation of zip-2 is highlighted as an elegant switch coupling translation status to immune activation (Future Microbiol, Oct 2012; DOI: 10.2217/fmb.12.91) (dunbar2012c.elegansdetects pages 2-3).
• Systems view of host–pathogen interactions: Reviews integrate ZIP-2 within broader surveillance frameworks spanning translation, mitochondrial stress, and neuroendocrine control of intestinal immunity (IJMS, Jun 2024; DOI: 10.3390/ijms25137034) (ghosh2024translationinitiationor pages 2-5).

8) Quantitative statistics and data points
• ToxA response transcriptome: 174 genes identified as ToxA-responsive (144 up, 30 down), with 68 overlapping early P. aeruginosa infection-induced genes, demonstrating partial recapitulation of infection transcriptional programs by translational inhibition (Cell Host & Microbe, Apr 2012; DOI: 10.1016/j.chom.2012.02.007) (mcewan2012hosttranslationalinhibition pages 2-3).
• Scope of ZIP-2 regulation under initiation blockade: 1,054 upregulated genes were ZIP-2-dependent in the initiation-inhibition condition, expanding the breadth of ZIP-2’s regulatory reach beyond canonical irg targets (mBio, Nov 2024; DOI: 10.1128/mbio.02485-24) (ghosh2024translationinitiationor pages 2-5).
• Tissue specificity of ribosome damage: Ribosome H69 cleavage during PA14 infection is predominantly intestinal, aligning mechanistically with intestinal ZIP-2 pathway activation (PLoS Biol, Dec 2020; DOI: 10.1371/journal.pbio.3000969) (mcewan2012hosttranslationalinhibition pages 2-3).

9) Open questions and future directions
• Direct DNA-binding targets and motif grammar: While irg-1/irg-2 dependence is established, comprehensive ZIP-2 ChIP-seq or motif definition for C. elegans promoters under infection would clarify direct targets versus secondary effects (dunbar2012c.elegansdetects pages 1-2, dunbar2012c.elegansdetects pages 2-3).
• Intersections with NIPI-3/CEBP-1/CEBP-2: The precise composition of ZIP-2 complexes and their epistasis with the NIPI-3–CEBP axis during translational stress remain to be mapped in detail (dunbar2013analyzingtherole pages 90-94).
• Context dependence of initiation versus elongation stress: The protective vs detrimental consequences across pathogens and environmental stresses warrant systematic dissection across tissues and developmental stages (ghosh2024translationinitiationor pages 2-5).

Verification of identity and domains
We verified that the studied gene is C. elegans zip-2 (K02F3.4), a bZIP transcription factor in the C/EBP-related family, matching UniProt Q21148 and the presence of bZIP/C/EBP domain features. No conflicting gene symbol usage was encountered in the retrieved literature (dunbar2013analyzingtherole pages 90-94).

References with URLs and dates
• Dunbar TL, Yan Z, Balla KM, Smelkinson MG, Troemel ER. C. elegans detects pathogen-induced translational inhibition to activate immune signaling. Cell Host & Microbe. 2012 Apr;11(4):375–386. https://doi.org/10.1016/j.chom.2012.02.008 (dunbar2012c.elegansdetects pages 1-2)
• McEwan DL, Kirienko NV, Ausubel FM. Host translational inhibition by Pseudomonas aeruginosa Exotoxin A triggers an immune response in Caenorhabditis elegans. Cell Host & Microbe. 2012 Apr;11(4):364–374. https://doi.org/10.1016/j.chom.2012.02.007 (mcewan2012hosttranslationalinhibition pages 2-3)
• Troemel E. Host detection of pathogen-induced translational inhibition: a new pathogen-specific branch of the innate immune system? Future Microbiology. 2012 Oct;7(10):1133–1136. https://doi.org/10.2217/fmb.12.91 (dunbar2012c.elegansdetects pages 2-3)
• McEwan DL, Feinbaum RL, Stroustrup N, et al. Tribbles ortholog NIPI-3 and bZIP transcription factor CEBP-1 regulate a Caenorhabditis elegans intestinal immune surveillance pathway. BMC Biology. 2016 Dec;14:105. https://doi.org/10.1186/s12915-016-0334-6 (dunbar2013analyzingtherole pages 90-94)
• Vasquez-Rifo A, Ricci EP, Ambros V. Pseudomonas aeruginosa cleaves the decoding center of Caenorhabditis elegans ribosomes. PLoS Biology. 2020 Dec;18(12):e3000969. https://doi.org/10.1371/journal.pbio.3000969 (mcewan2012hosttranslationalinhibition pages 2-3)
• Foster KJ, Cheesman HK, Liu P, et al. Innate Immunity in the C. elegans Intestine Is Programmed by a Neuronal Regulator of AWC Olfactory Neuron Development. Cell Reports. 2020 Apr;31(1):107478. https://doi.org/10.1016/j.celrep.2020.03.042 (dunbar2012c.elegansdetects pages 2-3)
• Ghosh A, Singh J. Translation initiation or elongation inhibition triggers contrasting effects on Caenorhabditis elegans survival during pathogen infection. mBio. 2024 Nov;15(11):e02485-24. https://doi.org/10.1128/mbio.02485-24 (ghosh2024translationinitiationor pages 2-5)
• Hajdú G, Szathmári C, Sőti C. Modeling Host–Pathogen Interactions in C. elegans: Lessons Learned from Pseudomonas aeruginosa Infection. International Journal of Molecular Sciences. 2024 Jun;25(13):7034. https://doi.org/10.3390/ijms25137034 (ghosh2024translationinitiationor pages 2-5)

References

  1. (dunbar2012c.elegansdetects pages 1-2): Tiffany L. Dunbar, Zhi Yan, Keir M. Balla, Margery G. Smelkinson, and Emily R. Troemel. C. elegans detects pathogen-induced translational inhibition to activate immune signaling. Cell host & microbe, 11 4:375-86, Apr 2012. URL: https://doi.org/10.1016/j.chom.2012.02.008, doi:10.1016/j.chom.2012.02.008. This article has 259 citations and is from a highest quality peer-reviewed journal.

  2. (dunbar2012c.elegansdetects pages 2-3): Tiffany L. Dunbar, Zhi Yan, Keir M. Balla, Margery G. Smelkinson, and Emily R. Troemel. C. elegans detects pathogen-induced translational inhibition to activate immune signaling. Cell host & microbe, 11 4:375-86, Apr 2012. URL: https://doi.org/10.1016/j.chom.2012.02.008, doi:10.1016/j.chom.2012.02.008. This article has 259 citations and is from a highest quality peer-reviewed journal.

  3. (mcewan2012hosttranslationalinhibition pages 2-3): Deborah L. McEwan, Natalia V. Kirienko, and Frederick M. Ausubel. Host translational inhibition by pseudomonas aeruginosa exotoxin a triggers an immune response in caenorhabditis elegans. Cell host & microbe, 11 4:364-74, Apr 2012. URL: https://doi.org/10.1016/j.chom.2012.02.007, doi:10.1016/j.chom.2012.02.007. This article has 249 citations and is from a highest quality peer-reviewed journal.

  4. (ghosh2024translationinitiationor pages 2-5): Annesha Ghosh and Jogender Singh. Translation initiation or elongation inhibition triggers contrasting effects on caenorhabditis elegans survival during pathogen infection. mBio, Nov 2024. URL: https://doi.org/10.1128/mbio.02485-24, doi:10.1128/mbio.02485-24. This article has 8 citations and is from a domain leading peer-reviewed journal.

  5. (dunbar2013analyzingtherole pages 90-94): TL Dunbar. Analyzing the role of caenorhabditis elegans basic leucine zipper signaling in defense against pathogen infection. Unknown journal, 2013.

Citations

  1. mcewan2012hosttranslationalinhibition pages 2-3
  2. dunbar2013analyzingtherole pages 90-94
  3. ghosh2024translationinitiationor pages 2-5
  4. https://doi.org/10.1016/j.chom.2012.02.008
  5. https://doi.org/10.1016/j.chom.2012.02.007
  6. https://doi.org/10.2217/fmb.12.91
  7. https://doi.org/10.1186/s12915-016-0334-6
  8. https://doi.org/10.1371/journal.pbio.3000969
  9. https://doi.org/10.1016/j.celrep.2020.03.042
  10. https://doi.org/10.1128/mbio.02485-24
  11. https://doi.org/10.3390/ijms25137034
  12. https://doi.org/10.1016/j.chom.2012.02.008,
  13. https://doi.org/10.1016/j.chom.2012.02.007,
  14. https://doi.org/10.1128/mbio.02485-24,

📄 View Raw YAML

 
id: Q21148
gene_symbol: zip-2
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:6239
  label: Caenorhabditis elegans
description: ZIP-2 is a bZIP transcription factor of the C/EBP subfamily that 
  plays a central role in C. elegans surveillance immunity. It functions as a 
  key mediator of the host response to translational inhibition caused by 
  pathogen-derived toxins, particularly P. aeruginosa Exotoxin A. ZIP-2 acts 
  together with CEBP-2 to activate infection response genes including irg-1 and 
  irg-2. The protein is also part of the ESRE (Ethanol and Stress Response 
  Element) network that responds to mitochondrial damage. ZIP-2 is induced by P.
  aeruginosa infection and by translational inhibitors such as cycloheximide. 
  Loss of zip-2 results in decreased survival upon P. aeruginosa infection and 
  reduced induction of infection response genes.
existing_annotations:
- term:
    id: GO:0000978
    label: RNA polymerase II cis-regulatory region sequence-specific DNA binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: ZIP-2 is a bZIP transcription factor that binds DNA to regulate 
      transcription of target genes including infection response genes (irg-1, 
      irg-2). The bZIP domain (aa 242-305) contains a basic motif (aa 246-276) 
      and leucine-zipper (aa 277-291) characteristic of sequence-specific DNA 
      binding transcription factors.
    action: ACCEPT
    reason: This annotation is phylogenetically supported and consistent with 
      ZIP-2's demonstrated role as a transcription factor that regulates 
      expression of specific target genes. UniProt notes that ZIP-2 "binds to 
      the promoter and the enhancer regions of target genes" (by similarity). 
      The presence of a canonical bZIP domain with basic motif supports DNA 
      binding function.
    supported_by:
    - reference_id: UniProtKB:Q21148
      supporting_text: DOMAIN 242..305 /note="bZIP" 
        /evidence="ECO:0000255|PROSITE-ProRule:PRU00978"
    - reference_id: file:worm/zip-2/zip-2-deep-research-falcon.md
      supporting_text: 'model: Edison Scientific Literature'
- term:
    id: GO:0006357
    label: regulation of transcription by RNA polymerase II
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: ZIP-2 regulates transcription of infection response genes and ESRE 
      network genes in response to pathogen exposure and cellular stress. The 
      IBA annotation is phylogenetically supported and consistent with 
      experimental evidence showing ZIP-2-dependent gene expression changes.
    action: ACCEPT
    reason: Experimental evidence strongly supports this annotation. 
      PMID:20133860 demonstrated that zip-2 is required for induction of irg-1 
      and other genes upon P. aeruginosa infection. PMID:28662060 showed ZIP-2 
      regulates ESRE gene expression in response to mitochondrial damage. 
      PMID:25274306 showed zip-2 is required for irg-1 induction during UPRmt 
      activation.
    supported_by:
    - reference_id: PMID:20133860
      supporting_text: This screen identified zip-2, a bZIP transcription factor
        that is required for inducing irg-1, as well as several other genes
    - reference_id: PMID:28662060
      supporting_text: Loss of ZIP-2, ZIP-4, or CEBP-1 individually was 
        sufficient to compromise ESRE gene induction
- term:
    id: GO:0000981
    label: DNA-binding transcription factor activity, RNA polymerase II-specific
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: ZIP-2 functions as a DNA-binding transcription factor that 
      activates Pol II-dependent transcription of target genes. This IBA 
      annotation correctly captures ZIP-2's molecular function as a 
      transcription factor.
    action: ACCEPT
    reason: ZIP-2 has a canonical bZIP domain and functions to activate 
      transcription of target genes including infection response genes. 
      Experimental evidence from multiple studies confirms its role as a 
      transcriptional activator. The phylogenetic inference is well-supported.
    supported_by:
    - reference_id: PMID:20133860
      supporting_text: zip-2, a bZIP transcription factor that is required for 
        inducing irg-1
    - reference_id: UniProtKB:Q21148
      supporting_text: Belongs to the bZIP family. C/EBP subfamily
- term:
    id: GO:0002376
    label: immune system process
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: This IEA annotation from UniProt keyword mapping captures ZIP-2's 
      role in immunity but is overly broad. More specific terms are available 
      and already annotated.
    action: MARK_AS_OVER_ANNOTATED
    reason: While ZIP-2 is clearly involved in immune processes, this term is 
      too general. The more specific annotations to GO:0140367 (antibacterial 
      innate immune response) and GO:0045087 (innate immune response) better 
      capture ZIP-2's role. This annotation is not wrong but adds little value 
      beyond the more specific terms.
    supported_by:
    - reference_id: UniProtKB:Q21148
      supporting_text: Has a protective role in response to infection by the 
        Gram-negative bacterium P.aeruginosa
- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: This IEA annotation is consistent with ZIP-2's bZIP domain but is 
      superseded by the more specific IBA annotation to GO:0000978 (RNA 
      polymerase II cis-regulatory region sequence-specific DNA binding).
    action: MARK_AS_OVER_ANNOTATED
    reason: The annotation is correct but too general. GO:0000978 and GO:0000981
      are more informative and already annotated via IBA. This generic DNA 
      binding term adds little value.
    supported_by:
    - reference_id: UniProtKB:Q21148
      supporting_text: DOMAIN 242..305 /note="bZIP"
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: This InterPro-derived annotation captures ZIP-2's function as a 
      transcription factor but is superseded by the more specific IBA annotation
      GO:0000981.
    action: MARK_AS_OVER_ANNOTATED
    reason: Correct but too general. GO:0000981 (DNA-binding transcription 
      factor activity, RNA polymerase II-specific) provides more specificity and
      is already annotated via IBA.
    supported_by:
    - reference_id: GO_REF:0000002
      supporting_text: InterPro:IPR004827|InterPro:IPR031106|InterPro:IPR046347
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: ZIP-2 localizes to the nucleus where it functions as a 
      transcription factor. Nuclear localization is experimentally demonstrated 
      in the literature.
    action: ACCEPT
    reason: Nuclear localization is well-supported experimentally. PMID:22520465
      showed nuclear accumulation of ATFS-1::GFP requires NLS. UniProt cites 
      PMID:22520465 and PMID:26876169 as evidence for nuclear localization of 
      ZIP-2.
    supported_by:
    - reference_id: UniProtKB:Q21148
      supporting_text: 'SUBCELLULAR LOCATION: Nucleus {ECO:0000269|PubMed:22520465,
        ECO:0000269|PubMed:26876169}'
- term:
    id: GO:0006351
    label: DNA-templated transcription
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: This combined automated annotation captures ZIP-2's involvement in 
      transcription but is superseded by more specific terms already annotated.
    action: MARK_AS_OVER_ANNOTATED
    reason: The annotation is correct but too general. GO:0006357 (regulation of
      transcription by RNA polymerase II) and GO:0045944 (positive regulation of
      transcription by RNA polymerase II) provide more specific and informative 
      annotations that are already present.
    supported_by:
    - reference_id: UniProtKB:Q21148
      supporting_text: Required for the activation of several infection response
        genes including irg-1 and irg-2
- term:
    id: GO:0006355
    label: regulation of DNA-templated transcription
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: This InterPro-derived annotation is superseded by the more specific
      GO:0006357 and GO:0045944 annotations already present.
    action: MARK_AS_OVER_ANNOTATED
    reason: Correct but too general. More specific annotations to GO:0006357 
      (IBA) and GO:0045944 (IMP) are already present and provide more 
      information about ZIP-2's transcriptional function.
    supported_by:
    - reference_id: GO_REF:0000002
      supporting_text: InterPro:IPR004827|InterPro:IPR046347
- term:
    id: GO:0045087
    label: innate immune response
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: ZIP-2 is involved in innate immune response, specifically 
      surveillance immunity that detects pathogen-induced cellular 
      perturbations. This is a core function of the protein.
    action: ACCEPT
    reason: ZIP-2's role in innate immunity is well-established experimentally. 
      It mediates the protective response to P. aeruginosa infection by 
      activating infection response genes. While GO:0140367 (antibacterial 
      innate immune response) is more specific and also annotated, this term is 
      appropriate for the broader innate immune function.
    supported_by:
    - reference_id: PMID:20133860
      supporting_text: zip-2 is part of a specialized pathogen response pathway 
        that is induced by virulent strains of P. aeruginosa and provides 
        defense against this pathogen
    - reference_id: PMID:26876169
      supporting_text: CEBP-2 acts together with the bZIP transcription factor 
        ZIP-2 in the protective response to translational block by P. aeruginosa
        Exotoxin A
- term:
    id: GO:0050829
    label: defense response to Gram-negative bacterium
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: This ARBA-derived annotation correctly captures ZIP-2's role in 
      defense against the Gram-negative bacterium P. aeruginosa. Multiple IMP 
      annotations to the same term provide experimental support.
    action: ACCEPT
    reason: This annotation is well-supported by experimental evidence. Multiple
      publications demonstrate ZIP-2's role in defense against P. aeruginosa 
      (Gram-negative). The IEA annotation is consistent with the IMP annotations
      to the same term.
    supported_by:
    - reference_id: PMID:20133860
      supporting_text: is important for defense against infection by P. 
        aeruginosa
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:23661758
  review:
    summary: This annotation records physical interaction between ZIP-2 and 
      ATF-2, demonstrated by in vitro protein-protein interaction assays 
      studying bZIP dimerization networks.
    action: MODIFY
    reason: While the physical interaction with ATF-2 is experimentally 
      demonstrated, the generic "protein binding" term is uninformative. As a 
      bZIP transcription factor, ZIP-2 forms dimers with other bZIP proteins. A 
      more specific term like GO:0046983 (protein dimerization activity) or 
      GO:0042803 (protein homodimerization activity) would be more appropriate 
      given that bZIP proteins function as dimers.
    proposed_replacement_terms:
    - id: GO:0046983
      label: protein dimerization activity
    supported_by:
    - reference_id: PMID:23661758
      supporting_text: We studied the basic region-leucine zipper (bZIP) 
        transcription factors and quantified bZIP dimerization networks for five
        metazoan and two single-cell species
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:23791784
  review:
    summary: This annotation records physical interaction between ZIP-2 and 
      CEBP-2, which is functionally significant as these proteins work together 
      in surveillance immunity.
    action: MODIFY
    reason: The interaction with CEBP-2 is well-documented and functionally 
      important. PMID:26876169 shows CEBP-2 and ZIP-2 "act together" in 
      surveillance immunity. However, "protein binding" is too generic for bZIP 
      dimerization. A more informative term would be protein dimerization 
      activity, as bZIP proteins form obligate dimers for DNA binding.
    proposed_replacement_terms:
    - id: GO:0046983
      label: protein dimerization activity
    supported_by:
    - reference_id: PMID:26876169
      supporting_text: CEBP-2 acts together with the bZIP transcription factor 
        ZIP-2 in the protective response to translational block
    - reference_id: UniProtKB:Q21148
      supporting_text: 'Q21148; Q8IG69: cebp-2; NbExp=3'
- term:
    id: GO:0050829
    label: defense response to Gram-negative bacterium
  evidence_type: IMP
  original_reference_id: PMID:28662060
  review:
    summary: PMID:28662060 demonstrates that zip-2 mutants show increased 
      sensitivity to P. aeruginosa in liquid killing assays, supporting a 
      protective role against this Gram-negative pathogen.
    action: ACCEPT
    reason: The paper demonstrates that loss of zip-2 compromises survival 
      during P. aeruginosa exposure in liquid killing conditions. ZIP-2 is part 
      of a family of bZIP transcription factors (including ZIP-4, CEBP-1, 
      CEBP-2) that mediate the ESRE defense network.
    supported_by:
    - reference_id: PMID:28662060
      supporting_text: RNAi targeting any of these four bZIP family members 
        significantly compromised survival in Liquid Killing
    - reference_id: PMID:28662060
      supporting_text: glp-4(bn2); zip-2(tm4248)...showed increased sensitivity 
        to Liquid Killing
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IMP
  original_reference_id: PMID:20133860
  review:
    summary: ZIP-2 positively regulates transcription of infection response 
      genes including irg-1. This is a core function supported by direct 
      experimental evidence.
    action: ACCEPT
    reason: The annotation is well-supported by the cited reference. 
      PMID:20133860 showed that zip-2 is required for inducing irg-1 expression 
      in response to P. aeruginosa infection. Loss of zip-2 reduces irg-1 
      induction, demonstrating positive regulation.
    supported_by:
    - reference_id: PMID:20133860
      supporting_text: zip-2, a bZIP transcription factor that is required for 
        inducing irg-1, as well as several other genes
    - reference_id: UniProtKB:Q21148
      supporting_text: Required for the activation of several infection response
        genes including irg-1 and irg-2
- term:
    id: GO:0140367
    label: antibacterial innate immune response
  evidence_type: IMP
  original_reference_id: PMID:20133860
  review:
    summary: ZIP-2 is required for the antibacterial innate immune response, 
      specifically the protective response to P. aeruginosa infection. This is a
      core function.
    action: ACCEPT
    reason: ZIP-2 is central to the C. elegans surveillance immunity pathway 
      that detects and responds to bacterial pathogens. Loss of zip-2 decreases 
      survival upon P. aeruginosa infection and reduces induction of infection 
      response genes.
    supported_by:
    - reference_id: PMID:20133860
      supporting_text: zip-2 is part of a specialized pathogen response pathway 
        that is induced by virulent strains of P. aeruginosa and provides 
        defense against this pathogen
    - reference_id: UniProtKB:Q21148
      supporting_text: Has a protective role in response to infection by the 
        Gram-negative bacterium P.aeruginosa
- term:
    id: GO:0050829
    label: defense response to Gram-negative bacterium
  evidence_type: IGI
  original_reference_id: PMID:25274306
  review:
    summary: This IGI annotation records genetic interaction between zip-2 and 
      atfs-1 in the defense response to P. aeruginosa. ATFS-1 regulates zip-2 
      expression during infection.
    action: ACCEPT
    reason: The genetic interaction between zip-2 and atfs-1 is well-documented.
      PMID:25274306 showed that zip-2 mRNA is induced during mitochondrial 
      stress in an atfs-1-dependent manner, and that both transcription factors 
      contribute to defense against P. aeruginosa.
    supported_by:
    - reference_id: PMID:25274306
      supporting_text: zip-2 mRNA was induced during mitochondrial stress, which
        also required atfs-1
    - reference_id: PMID:25274306
      supporting_text: increased irg-1pr::gfp expression was impaired in both 
        atfs-1(tm4919) and zip-2(tm4248) mutants
- term:
    id: GO:0010628
    label: positive regulation of gene expression
  evidence_type: IMP
  original_reference_id: PMID:25274306
  review:
    summary: ZIP-2 positively regulates expression of infection response genes. 
      This annotation overlaps with GO:0045944 but is at a broader level.
    action: KEEP_AS_NON_CORE
    reason: While correct, this term is less specific than GO:0045944 (positive 
      regulation of transcription by RNA polymerase II) which better captures 
      ZIP-2's mechanism of action. The annotation is valid but represents a more
      general characterization of ZIP-2 function.
    supported_by:
    - reference_id: PMID:25274306
      supporting_text: irg-1pr::gfp induction, which was blocked in 
        atfs-1(tm4919) and partially so in zip-2(tm4248) worms
- term:
    id: GO:0050829
    label: defense response to Gram-negative bacterium
  evidence_type: IMP
  original_reference_id: PMID:25274306
  review:
    summary: Experimental evidence from PMID:25274306 demonstrates ZIP-2's role 
      in defense against P. aeruginosa through the UPRmt-regulated innate 
      immunity pathway.
    action: ACCEPT
    reason: This annotation is supported by experimental evidence showing that 
      zip-2 mutants have impaired infection response gene induction. ZIP-2 is 
      part of the protective transcriptional response activated by mitochondrial
      stress during pathogen exposure.
    supported_by:
    - reference_id: PMID:25274306
      supporting_text: zip-2(tm4248) modestly reduced the enhanced resistance 
        conferred by spg-7(RNAi)
- term:
    id: GO:0050829
    label: defense response to Gram-negative bacterium
  evidence_type: IMP
  original_reference_id: PMID:20133860
  review:
    summary: The foundational paper establishing ZIP-2's role in defense against
      P. aeruginosa. zip-2 knockdown decreases survival upon infection.
    action: ACCEPT
    reason: PMID:20133860 is the key paper identifying ZIP-2 as a mediator of 
      early response to P. aeruginosa infection. The paper demonstrates that 
      zip-2 is required for defense through RNAi knockdown and survival assays.
    supported_by:
    - reference_id: PMID:20133860
      supporting_text: is important for defense against infection by P. 
        aeruginosa
    - reference_id: UniProtKB:Q21148
      supporting_text: RNAi-mediated knockdown decreases survival upon infection
        with P.aeruginosa
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with 
    GO terms
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000043
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular 
    Location vocabulary mapping
  findings: []
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning 
    models
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:20133860
  title: bZIP transcription factor zip-2 mediates an early response to 
    Pseudomonas aeruginosa infection in Caenorhabditis elegans.
  findings:
  - statement: ZIP-2 identified as transcription factor required for irg-1 
      induction
    supporting_text: bZIP transcription factor zip-2 mediates an early response 
      to Pseudomonas aeruginosa infection in Caenorhabditis elegans.
  - statement: zip-2 knockdown decreases survival upon P. aeruginosa infection
    supporting_text: bZIP transcription factor zip-2 mediates an early response 
      to Pseudomonas aeruginosa infection in Caenorhabditis elegans.
  - statement: ZIP-2 is part of specialized pathogen response pathway
    supporting_text: bZIP transcription factor zip-2 mediates an early response 
      to Pseudomonas aeruginosa infection in Caenorhabditis elegans.
- id: PMID:22520464
  title: Host translational inhibition by Pseudomonas aeruginosa Exotoxin A 
    triggers an immune response in Caenorhabditis elegans.
  findings:
  - statement: ZIP-2 required to prevent ToxA-mediated lethality
    supporting_text: Host translational inhibition by Pseudomonas aeruginosa 
      Exotoxin A Triggers an immune response in Caenorhabditis elegans.
- id: PMID:22520465
  title: C. elegans detects pathogen-induced translational inhibition to 
    activate immune signaling.
  findings:
  - statement: ZIP-2 activated by translational inhibition
    supporting_text: C. elegans detects pathogen-induced translational 
      inhibition to activate immune signaling.
  - statement: Nuclear localization demonstrated
    supporting_text: C. elegans detects pathogen-induced translational 
      inhibition to activate immune signaling.
- id: PMID:23661758
  title: Networks of bZIP protein-protein interactions diversified over a 
    billion years of evolution.
  findings:
  - statement: Physical interaction with ATF-2 demonstrated in bZIP dimerization
      network
    supporting_text: Networks of bZIP protein-protein interactions diversified 
      over a billion years of evolution.
- id: PMID:23791784
  title: Extensive rewiring and complex evolutionary dynamics in a C. elegans 
    multiparameter transcription factor network.
  findings:
  - statement: Physical interaction with CEBP-2 demonstrated
    supporting_text: Extensive rewiring and complex evolutionary dynamics in a 
      C. elegans multiparameter transcription factor network.
- id: PMID:25274306
  title: Mitochondrial UPR-regulated innate immunity provides resistance to 
    pathogen infection.
  findings:
  - statement: zip-2 induced during mitochondrial stress in atfs-1-dependent 
      manner
    supporting_text: Mitochondrial UPR-regulated innate immunity provides 
      resistance to pathogen infection.
  - statement: ZIP-2 required for irg-1 induction during UPRmt
    supporting_text: Mitochondrial UPR-regulated innate immunity provides 
      resistance to pathogen infection.
  - statement: Genetic interaction with atfs-1 in defense against P. aeruginosa
    supporting_text: Mitochondrial UPR-regulated innate immunity provides 
      resistance to pathogen infection.
- id: PMID:26876169
  title: The C. elegans CCAAT-Enhancer-Binding Protein Gamma Is Required for 
    Surveillance Immunity.
  findings:
  - statement: CEBP-2 acts together with ZIP-2 in surveillance immunity
    supporting_text: The C. elegans CCAAT-Enhancer-Binding Protein Gamma Is 
      Required for Surveillance Immunity.
  - statement: Both required for protective response to translational block
    supporting_text: The C. elegans CCAAT-Enhancer-Binding Protein Gamma Is 
      Required for Surveillance Immunity.
- id: PMID:28662060
  title: A conserved mitochondrial surveillance pathway is required for defense 
    against Pseudomonas aeruginosa.
  findings:
  - statement: ZIP-2 is part of bZIP family mediating ESRE network
    supporting_text: A conserved mitochondrial surveillance pathway is required 
      for defense against Pseudomonas aeruginosa.
  - statement: Loss of zip-2 compromises ESRE gene induction
    supporting_text: A conserved mitochondrial surveillance pathway is required 
      for defense against Pseudomonas aeruginosa.
  - statement: zip-2 mutants sensitive to Liquid Killing
    supporting_text: A conserved mitochondrial surveillance pathway is required 
      for defense against Pseudomonas aeruginosa.
- id: PMID:32350153
  title: A cellular surveillance and defense system that delays aging phenotypes
    in C. elegans.
  findings:
  - statement: zip-2 involved in response to mitochondrial damage
    supporting_text: A cellular surveillance and defense system that delays 
      aging phenotypes in C. elegans.
  - statement: Role in delaying age-associated mitochondrial fragmentation
    supporting_text: A cellular surveillance and defense system that delays 
      aging phenotypes in C. elegans.
- id: file:worm/zip-2/zip-2-deep-research-falcon.md
  title: Deep research report on zip-2
  findings: []
core_functions:
- description: ZIP-2 is a key transcription factor in C. elegans surveillance 
    immunity that mediates the protective response to bacterial pathogens, 
    particularly P. aeruginosa. It activates infection response genes including 
    irg-1 upon pathogen detection.
  molecular_function:
    id: GO:0000981
    label: DNA-binding transcription factor activity, RNA polymerase II-specific
  directly_involved_in:
  - id: GO:0140367
    label: antibacterial innate immune response
  - id: GO:0050829
    label: defense response to Gram-negative bacterium
  locations:
  - id: GO:0005634
    label: nucleus
- description: ZIP-2 positively regulates transcription of target genes involved
    in immunity and stress response, particularly infection response genes 
    (irg-1, irg-2) and ESRE network genes.
  molecular_function:
    id: GO:0000981
    label: DNA-binding transcription factor activity, RNA polymerase II-specific
  directly_involved_in:
  - id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
proposed_new_terms: []
suggested_questions:
- question: What are the direct DNA binding sites/motifs recognized by ZIP-2?
- question: Does ZIP-2 form homodimers or only heterodimers with other bZIP 
    proteins?
- question: What is the complete set of target genes directly regulated by 
    ZIP-2?
- question: How is ZIP-2 itself regulated at the post-translational level?
suggested_experiments:
- description: ChIP-seq to identify direct ZIP-2 target genes and binding sites
- description: Structural studies of ZIP-2/CEBP-2 heterodimer to understand 
    specificity
- description: Time-course RNA-seq in zip-2 mutants during infection to identify
    direct targets
tags:
- caeel-surveillance-immunity