id: P27540
gene_symbol: ARNT
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >-
  ARNT encodes aryl hydrocarbon receptor nuclear translocator, also known as HIF-1 beta, a broadly expressed
  nuclear bHLH-PAS transcription factor subunit. ARNT dimerizes with AHR, HIF-alpha proteins, and other
  bHLH-PAS partners through PAS-domain interfaces, and the resulting complexes bind cis-regulatory DNA
  elements such as xenobiotic/dioxin response elements and hypoxia response elements to regulate RNA polymerase
  II transcription. Through these heterodimeric complexes, ARNT participates in xenobiotic response, hypoxia
  adaptation, angiogenic and metabolic gene regulation, and selected immune and developmental transcriptional
  programs. The primary molecular roles are sequence-specific regulatory DNA binding and partner-specific
  transcription factor dimerization in the nucleus.
alternative_products:
- name: 1 (Long)
  id: P27540-1
- name: 2 (Short)
  id: P27540-2
  sequence_note: VSP_002092
- name: '3'
  id: P27540-3
  sequence_note: VSP_036532, VSP_036533
- name: '4'
  id: P27540-4
  sequence_note: VSP_055030
existing_annotations:
- term:
    id: GO:0006357
    label: regulation of transcription by RNA polymerase II
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: >-
      regulation of transcription by RNA polymerase II is supported by ARNT-containing AHR and HIF transcriptional
      regulatory complexes.
    action: ACCEPT
    reason: >-
      ARNT-containing heterodimers activate and regulate RNA polymerase II target genes in hypoxia and
      xenobiotic-response pathways. This is a central biological role of the protein.
    supported_by:
    - &id003
      reference_id: PMID:7539918
      supporting_text: >-
        HIF-1 beta is a series of ARNT gene products, which can thus heterodimerize with either HIF-1
        alpha or AHR.
    - &id004
      reference_id: PMID:8756616
      supporting_text: >-
        VEGF mRNA was not induced by hypoxia in mutant cells that do not express the HIF-1beta (ARNT)
        subunit.
    - &id005
      reference_id: PMID:30429208
      supporting_text: >-
        In contrast, HIF‐β is constitutively expressed 11. In hypoxia, HIF‐α polypeptides escape destruction
        and are able to associate with HIF‐β to drive transcriptional responses 4.
    - &id001
      reference_id: PMID:1317062
      supporting_text: >-
        The ligand-bound receptor activates Cyp 1a1 gene transcription through interaction with specific
        DNA sequences, termed xenobiotic responsive elements (XREs).
    - &id002
      reference_id: PMID:28396409
      supporting_text: >-
        We determined the crystal structure of the mammalian AHR-ARNT heterodimer in complex with the
        DRE.
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: >-
      nucleus is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0034751
    label: aryl hydrocarbon receptor complex
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: part_of
  review:
    summary: >-
      aryl hydrocarbon receptor complex is directly supported for ARNT-containing AHR complexes.
    action: ACCEPT
    reason: >-
      ARNT is the required nuclear translocator/dimerization partner of AHR and is a structural component
      of the DNA-binding AHR complex.
    supported_by: &id010
    - *id001
    - *id002
    - &id015
      reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
        including hypoxia-inducible factors (HIF)18, single-minded proteins (SIM)19 or the estrogen receptor
        (ER)20.
- term:
    id: GO:0000978
    label: RNA polymerase II cis-regulatory region sequence-specific DNA binding
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: >-
      RNA polymerase II cis-regulatory region sequence-specific DNA binding is consistent with ARNT-containing
      AHR and HIF transcription factor complexes binding regulatory DNA.
    action: ACCEPT
    reason: >-
      ARNT is a bHLH-PAS transcription factor subunit. Primary AHR and HIF studies show ARNT-containing
      heterodimers binding DRE/XRE or HRE-like regulatory DNA and activating transcription.
    supported_by:
    - &id006
      reference_id: PMID:1317062
      supporting_text: >-
        Arnt is now shown to be a structural component of the XRE binding form of the Ah receptor.
    - &id007
      reference_id: PMID:7539918
      supporting_text: >-
        HIF-1 beta is a series of ARNT gene products, which can thus heterodimerize with either HIF-1
        alpha or AHR.
    - &id008
      reference_id: PMID:28396409
      supporting_text: >-
        The AHR forms a transcriptionally active heterodimer with ARNT (AHR nuclear translocator), which
        recognizes the dioxin response element (DRE) in the promoter of downstream genes.
    - *id003
- term:
    id: GO:0001666
    label: response to hypoxia
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  qualifier: involved_in
  review:
    summary: >-
      response to hypoxia is supported through ARNT/HIF transcriptional response to low oxygen.
    action: ACCEPT
    reason: >-
      ARNT is HIF-1 beta, the constitutive dimerization partner for HIF-alpha proteins. Loss of ARNT/HIF-1
      beta disrupts hypoxia-inducible VEGF expression, and HIF-alpha:ARNT complexes drive hypoxia transcriptional
      programs.
    supported_by: &id014
    - *id003
    - *id004
    - *id005
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: enables
  review:
    summary: >-
      The broad DNA-binding transcription factor annotation is directionally correct but should be represented
      by RNA polymerase II-specific DNA-binding transcription factor terms.
    action: MODIFY
    reason: >-
      ARNT is not a generic transcription factor; its curated role is as a bHLH-PAS subunit of RNA polymerase
      II regulatory complexes that bind defined cis-regulatory DNA elements. A more specific Pol II DNA-binding
      transcription factor term is preferable.
    proposed_replacement_terms: &id017
    - id: GO:0000978
      label: RNA polymerase II cis-regulatory region sequence-specific DNA binding
    - id: GO:0000981
      label: DNA-binding transcription factor activity, RNA polymerase II-specific
    supported_by: &id009
    - *id006
    - *id007
    - *id008
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: located_in
  review:
    summary: >-
      nucleus is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0005667
    label: transcription regulator complex
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: part_of
  review:
    summary: >-
      Transcription regulator complex is true but too broad.
    action: MODIFY
    reason: >-
      ARNT is part of RNA polymerase II transcription regulatory complexes, including AHR-ARNT and HIF-alpha:ARNT
      complexes. The Pol II-specific complex term is more informative.
    proposed_replacement_terms:
    - id: GO:0090575
      label: RNA polymerase II transcription regulator complex
    supported_by: *id009
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: located_in
  review:
    summary: >-
      Cytoplasm is not supported as a stable ARNT localization in the reviewed evidence.
    action: REMOVE
    reason: >-
      ARNT is principally nuclear and functions in nuclear transcription factor complexes. Cytoplasmic
      AHR trafficking should not be transferred to ARNT as a cytoplasmic localization without direct evidence.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0006355
    label: regulation of DNA-templated transcription
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: involved_in
  review:
    summary: >-
      The annotation is directionally correct but too broad.
    action: MODIFY
    reason: >-
      ARNT regulates RNA polymerase II transcription as part of AHR/HIF-family complexes, so the Pol II-specific
      transcription regulation term already present in GOA is preferable.
    proposed_replacement_terms:
    - id: GO:0006357
      label: regulation of transcription by RNA polymerase II
    supported_by: *id009
- term:
    id: GO:0030522
    label: intracellular receptor signaling pathway
  evidence_type: IEA
  original_reference_id: GO_REF:0000108
  qualifier: involved_in
  review:
    summary: >-
      Intracellular receptor signaling pathway is plausible but broad for ARNT.
    action: KEEP_AS_NON_CORE
    reason: >-
      ARNT contributes to ligand-activated AHR signaling, but ARNT itself is not the ligand-binding receptor.
      More specific AHR complex, AHR binding, and transcription regulation annotations better capture
      the function.
    supported_by: *id010
- term:
    id: GO:0046983
    label: protein dimerization activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: >-
      Generic protein dimerization is supported but should be replaced by the more informative heterodimerization
      activity.
    action: MODIFY
    reason: >-
      ARNT primarily functions by heterodimerizing with AHR, HIF1A/EPAS1, and other bHLH-PAS partners.
      The broad dimerization term loses the biologically important partner-specific heterodimer context.
    proposed_replacement_terms: &id011
    - id: GO:0046982
      label: protein heterodimerization activity
    supported_by:
    - &id012
      reference_id: PMID:16181639
      supporting_text: >-
        ARNT is a promiscuous bHLH-PAS (Per-ARNT-Sim) protein that forms heterodimeric transcriptional
        regulator complexes with several other bHLH-PAS subunits.
    - &id013
      reference_id: PMID:16181639
      supporting_text: >-
        we have solved the solution structure of the corresponding PAS domain of ARNT and show that it
        utilizes a very similar interface for the interaction with the HIF-2alpha PAS domain.
    - *id001
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:10395741
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:11018023
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: *id011
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:14668441
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: *id011
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:19129502
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: *id011
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20562859
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20603618
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20932347
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:21620138
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:23434853
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: *id011
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:24434214
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:24981860
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:28514442
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:33961781
  qualifier: enables
  review:
    summary: >-
      The generic protein binding annotation is not informative as a gene-function statement.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The interaction may be experimentally detected, but protein binding alone does not describe ARNT
      molecular function and several cited records come from large-scale or pathway-context interaction
      studies. ARNT function is better captured by specific transcription factor dimerization, AHR binding,
      DNA binding, and transcription regulatory complex terms.
    supported_by: *id009
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:9704006
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: *id011
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0000978
    label: RNA polymerase II cis-regulatory region sequence-specific DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: enables
  review:
    summary: >-
      RNA polymerase II cis-regulatory region sequence-specific DNA binding is consistent with ARNT-containing
      AHR and HIF transcription factor complexes binding regulatory DNA.
    action: ACCEPT
    reason: >-
      ARNT is a bHLH-PAS transcription factor subunit. Primary AHR and HIF studies show ARNT-containing
      heterodimers binding DRE/XRE or HRE-like regulatory DNA and activating transcription.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0004879
    label: nuclear receptor activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: contributes_to
  review:
    summary: >-
      Nuclear receptor activity is not an ideal term for ARNT.
    action: MODIFY
    reason: >-
      ARNT does not itself bind ligand as a receptor. The evidence supports ARNT contribution to AHR-containing
      transcription factor complexes, so AHR binding and RNA polymerase II DNA-binding transcription factor
      activity are better replacements.
    proposed_replacement_terms:
    - id: GO:0017162
      label: aryl hydrocarbon receptor binding
    - id: GO:0000981
      label: DNA-binding transcription factor activity, RNA polymerase II-specific
    supported_by: *id010
- term:
    id: GO:0033235
    label: positive regulation of protein sumoylation
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: involved_in
  review:
    summary: >-
      Positive regulation of protein sumoylation is not supported as a core ARNT function in this review.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      ARNT can be present in HIF/AHR regulatory contexts where partner proteins are post-translationally
      modified, but the reviewed primary ARNT function is transcription-factor dimerization and DNA binding.
      This electronic transfer should not be promoted in the PN review without direct ARNT-specific evidence.
    supported_by:
    - &id016
      reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        Required for activity of the AHR. Upon ligand binding, AHR translocates into the nucleus, where
        it heterodimerizes with ARNT and induces transcription by binding to xenobiotic response elements
        (XRE).
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        The heterodimer binds to core DNA sequence 5'-TACGTG-3' within the hypoxia response element (HRE)
        of target gene promoters and functions as a transcriptional regulator of the adaptive response
        to hypoxia.
    - *id006
    - *id007
    - *id008
- term:
    id: GO:0043565
    label: sequence-specific DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: enables
  review:
    summary: >-
      sequence-specific DNA binding is true but less specific than the supported Pol II cis-regulatory
      DNA-binding role.
    action: MODIFY
    reason: >-
      The primary evidence concerns ARNT-containing AHR/HIF transcription factor complexes binding DRE/XRE
      or HRE cis-regulatory elements. The annotation should use the Pol II cis-regulatory DNA-binding
      term rather than a generic sequence-specific DNA-binding term.
    proposed_replacement_terms:
    - id: GO:0000978
      label: RNA polymerase II cis-regulatory region sequence-specific DNA binding
    supported_by: *id009
- term:
    id: GO:0046982
    label: protein heterodimerization activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: enables
  review:
    summary: >-
      ARNT heterodimerization is a core molecular function.
    action: ACCEPT
    reason: >-
      Multiple structural and functional studies show ARNT forming heterodimers with AHR and HIF-alpha
      proteins through bHLH-PAS/PAS-B interfaces; these heterodimers are the active transcriptional regulatory
      complexes.
    supported_by:
    - *id012
    - *id013
    - *id001
    - *id002
- term:
    id: GO:1990837
    label: sequence-specific double-stranded DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  qualifier: enables
  review:
    summary: >-
      sequence-specific double-stranded DNA binding is consistent with ARNT-containing AHR and HIF transcription
      factor complexes binding regulatory DNA.
    action: ACCEPT
    reason: >-
      ARNT is a bHLH-PAS transcription factor subunit. Primary AHR and HIF studies show ARNT-containing
      heterodimers binding DRE/XRE or HRE-like regulatory DNA and activating transcription.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:10085255
  qualifier: located_in
  review:
    summary: >-
      nucleus is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0006357
    label: regulation of transcription by RNA polymerase II
  evidence_type: NAS
  original_reference_id: PMID:23033253
  qualifier: involved_in
  review:
    summary: >-
      regulation of transcription by RNA polymerase II is supported by ARNT-containing AHR and HIF transcriptional
      regulatory complexes.
    action: ACCEPT
    reason: >-
      ARNT-containing heterodimers activate and regulate RNA polymerase II target genes in hypoxia and
      xenobiotic-response pathways. This is a central biological role of the protein.
    supported_by:
    - *id003
    - *id004
    - *id005
    - *id001
    - *id002
- term:
    id: GO:0090575
    label: RNA polymerase II transcription regulator complex
  evidence_type: IPI
  original_reference_id: PMID:23033253
  qualifier: part_of
  review:
    summary: >-
      ARNT is part of RNA polymerase II transcription regulator complexes.
    action: ACCEPT
    reason: >-
      HIF and AHR transcription complexes contain ARNT and regulate Pol II target genes through HRE/DRE
      regulatory elements.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0006357
    label: regulation of transcription by RNA polymerase II
  evidence_type: NAS
  original_reference_id: PMID:23434853
  qualifier: involved_in
  review:
    summary: >-
      regulation of transcription by RNA polymerase II is supported by ARNT-containing AHR and HIF transcriptional
      regulatory complexes.
    action: ACCEPT
    reason: >-
      ARNT-containing heterodimers activate and regulate RNA polymerase II target genes in hypoxia and
      xenobiotic-response pathways. This is a central biological role of the protein.
    supported_by:
    - *id003
    - *id004
    - *id005
    - *id001
    - *id002
- term:
    id: GO:0071456
    label: cellular response to hypoxia
  evidence_type: NAS
  original_reference_id: PMID:30429208
  qualifier: involved_in
  review:
    summary: >-
      cellular response to hypoxia is supported through ARNT/HIF transcriptional response to low oxygen.
    action: ACCEPT
    reason: >-
      ARNT is HIF-1 beta, the constitutive dimerization partner for HIF-alpha proteins. Loss of ARNT/HIF-1
      beta disrupts hypoxia-inducible VEGF expression, and HIF-alpha:ARNT complexes drive hypoxia transcriptional
      programs.
    supported_by: *id014
- term:
    id: GO:0090575
    label: RNA polymerase II transcription regulator complex
  evidence_type: IPI
  original_reference_id: PMID:23434853
  qualifier: part_of
  review:
    summary: >-
      ARNT is part of RNA polymerase II transcription regulator complexes.
    action: ACCEPT
    reason: >-
      HIF and AHR transcription complexes contain ARNT and regulate Pol II target genes through HRE/DRE
      regulatory elements.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: IDA
  original_reference_id: GO_REF:0000052
  qualifier: located_in
  review:
    summary: >-
      nucleoplasm is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0006805
    label: xenobiotic metabolic process
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-8937144
  qualifier: involved_in
  review:
    summary: >-
      Xenobiotic metabolic process is supported through the AHR-ARNT transcriptional response.
    action: ACCEPT
    reason: >-
      ARNT is required for ligand-activated AHR transcriptional complexes that bind xenobiotic response
      elements and induce detoxification/metabolic genes. This is a core AHR-ARNT biological role.
    supported_by:
    - *id001
    - *id002
    - *id015
    - *id016
- term:
    id: GO:0016604
    label: nuclear body
  evidence_type: IDA
  original_reference_id: GO_REF:0000052
  qualifier: located_in
  review:
    summary: >-
      Nuclear body localization is HPA-supported but peripheral to ARNT function.
    action: KEEP_AS_NON_CORE
    reason: >-
      The localization may describe an observed nuclear subcompartment signal, but ARNT core function
      is in transcription factor complexes and regulatory DNA binding rather than nuclear-body biology.
    supported_by:
    - reference_id: GO_REF:0000052
      supporting_text: >-
        [HPA immunofluorescence-derived GO cellular-component annotation]
- term:
    id: GO:0001228
    label: DNA-binding transcription activator activity, RNA polymerase II-specific
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-8937177
  qualifier: enables
  review:
    summary: >-
      DNA-binding transcription activator activity, RNA polymerase II-specific captures the transcription-factor
      activity of ARNT-containing RNA polymerase II regulatory complexes.
    action: ACCEPT
    reason: >-
      The activity is best interpreted as the activity of ARNT-containing heterodimers. ARNT contributes
      DNA-binding and PAS-dimerization surfaces to AHR/HIF complexes that regulate Pol II target genes.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id012
- term:
    id: GO:0045821
    label: positive regulation of glycolytic process
  evidence_type: IDA
  original_reference_id: PMID:8089148
  qualifier: acts_upstream_of
  review:
    summary: >-
      Positive regulation of glycolysis is a supported downstream HIF pathway output, but not ARNT molecular
      core function.
    action: KEEP_AS_NON_CORE
    reason: >-
      The cited study shows HIF-1-mediated induction of glycolytic enzyme genes under hypoxia. Because
      ARNT is HIF-1 beta, this is biologically plausible, but it is a downstream transcriptional program
      rather than a direct proteostasis or adaptor role.
    supported_by:
    - reference_id: PMID:8089148
      supporting_text: >-
        RNAs encoding the glycolytic enzymes aldolase A (ALDA), phosphoglycerate kinase 1 (PGK1), and
        pyruvate kinase M were induced by exposure of Hep3B or HeLa cells to inducers of HIF-1
    - reference_id: PMID:8089148
      supporting_text: >-
        These results support the role of HIF-1 as a mediator of adaptive responses to hypoxia
- term:
    id: GO:0034599
    label: cellular response to oxidative stress
  evidence_type: IDA
  original_reference_id: PMID:8089148
  qualifier: involved_in
  review:
    summary: >-
      Cellular response to oxidative stress is too indirect for the cited ARNT/HIF glycolysis paper.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      PMID:8089148 supports HIF-dependent hypoxia-responsive glycolytic gene transcription, not a direct
      ARNT role in oxidative-stress response. Hypoxia-response annotations already capture the supported
      biology.
    supported_by:
    - reference_id: PMID:8089148
      supporting_text: >-
        These results support the role of HIF-1 as a mediator of adaptive responses to hypoxia
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IDA
  original_reference_id: PMID:8089148
  qualifier: involved_in
  review:
    summary: >-
      positive regulation of transcription by RNA polymerase II is supported by ARNT-containing AHR and
      HIF transcriptional regulatory complexes.
    action: ACCEPT
    reason: >-
      ARNT-containing heterodimers activate and regulate RNA polymerase II target genes in hypoxia and
      xenobiotic-response pathways. This is a central biological role of the protein.
    supported_by:
    - *id003
    - *id004
    - *id005
    - *id001
    - *id002
- term:
    id: GO:0050728
    label: negative regulation of inflammatory response
  evidence_type: IDA
  original_reference_id: PMID:29454749
  qualifier: involved_in
  review:
    summary: >-
      Negative regulation of inflammatory response is plausible through AHR-ARNT epithelial signaling,
      but it is not a core ARNT molecular function.
    action: KEEP_AS_NON_CORE
    reason: >-
      The cited study supports microbiota-derived indole metabolites activating AHR-dependent IL-10 receptor
      regulation and anti-inflammatory pathways. ARNT is the AHR transcriptional partner, but the anti-inflammatory
      phenotype is pathway-level and context-specific.
    supported_by:
    - reference_id: PMID:29454749
      supporting_text: >-
        Administration of indole metabolites showed prominent induction of IL-10R1 on cultured intestinal
        epithelia that was explained by activation of the aryl hydrocarbon receptor.
    - reference_id: PMID:29454749
      supporting_text: >-
        This work defines a novel role of indole metabolites in anti-inflammatory pathways mediated by
        epithelial IL-10 signaling
- term:
    id: GO:0004879
    label: nuclear receptor activity
  evidence_type: IDA
  original_reference_id: PMID:34521881
  qualifier: contributes_to
  review:
    summary: >-
      Nuclear receptor activity is not an ideal term for ARNT.
    action: MODIFY
    reason: >-
      ARNT does not itself bind ligand as a receptor. The evidence supports ARNT contribution to AHR-containing
      transcription factor complexes, so AHR binding and RNA polymerase II DNA-binding transcription factor
      activity are better replacements.
    proposed_replacement_terms:
    - id: GO:0017162
      label: aryl hydrocarbon receptor binding
    - id: GO:0000981
      label: DNA-binding transcription factor activity, RNA polymerase II-specific
    supported_by: *id010
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:34521881
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: &id018
    - id: GO:0017162
      label: aryl hydrocarbon receptor binding
    - id: GO:0046982
      label: protein heterodimerization activity
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:34521881
  qualifier: located_in
  review:
    summary: >-
      nucleus is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0034753
    label: nuclear aryl hydrocarbon receptor complex
  evidence_type: IDA
  original_reference_id: PMID:34521881
  qualifier: is_active_in
  review:
    summary: >-
      nuclear aryl hydrocarbon receptor complex is directly supported for ARNT-containing AHR complexes.
    action: ACCEPT
    reason: >-
      ARNT is the required nuclear translocator/dimerization partner of AHR and is a structural component
      of the DNA-binding AHR complex.
    supported_by: *id010
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IDA
  original_reference_id: PMID:34521881
  qualifier: involved_in
  review:
    summary: >-
      positive regulation of transcription by RNA polymerase II is supported by ARNT-containing AHR and
      HIF transcriptional regulatory complexes.
    action: ACCEPT
    reason: >-
      ARNT-containing heterodimers activate and regulate RNA polymerase II target genes in hypoxia and
      xenobiotic-response pathways. This is a central biological role of the protein.
    supported_by:
    - *id003
    - *id004
    - *id005
    - *id001
    - *id002
- term:
    id: GO:0046982
    label: protein heterodimerization activity
  evidence_type: IDA
  original_reference_id: PMID:34521881
  qualifier: enables
  review:
    summary: >-
      ARNT heterodimerization is a core molecular function.
    action: ACCEPT
    reason: >-
      Multiple structural and functional studies show ARNT forming heterodimers with AHR and HIF-alpha
      proteins through bHLH-PAS/PAS-B interfaces; these heterodimers are the active transcriptional regulatory
      complexes.
    supported_by:
    - *id012
    - *id013
    - *id001
    - *id002
- term:
    id: GO:1990837
    label: sequence-specific double-stranded DNA binding
  evidence_type: IDA
  original_reference_id: PMID:34521881
  qualifier: enables
  review:
    summary: >-
      sequence-specific double-stranded DNA binding is consistent with ARNT-containing AHR and HIF transcription
      factor complexes binding regulatory DNA.
    action: ACCEPT
    reason: >-
      ARNT is a bHLH-PAS transcription factor subunit. Primary AHR and HIF studies show ARNT-containing
      heterodimers binding DRE/XRE or HRE-like regulatory DNA and activating transcription.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: IDA
  original_reference_id: PMID:29454749
  qualifier: enables
  review:
    summary: >-
      The broad DNA-binding transcription factor annotation is directionally correct but should be represented
      by RNA polymerase II-specific DNA-binding transcription factor terms.
    action: MODIFY
    reason: >-
      ARNT is not a generic transcription factor; its curated role is as a bHLH-PAS subunit of RNA polymerase
      II regulatory complexes that bind defined cis-regulatory DNA elements. A more specific Pol II DNA-binding
      transcription factor term is preferable.
    proposed_replacement_terms: *id017
    supported_by: *id009
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IC
  original_reference_id: PMID:28602820
  qualifier: is_active_in
  review:
    summary: >-
      nucleus is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-1234167
  qualifier: located_in
  review:
    summary: >-
      nucleoplasm is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-1234171
  qualifier: located_in
  review:
    summary: >-
      nucleoplasm is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-8936851
  qualifier: located_in
  review:
    summary: >-
      nucleoplasm is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-8937177
  qualifier: located_in
  review:
    summary: >-
      nucleoplasm is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: TAS
  original_reference_id: Reactome:R-HSA-9634850
  qualifier: located_in
  review:
    summary: >-
      nucleoplasm is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0061629
    label: RNA polymerase II-specific DNA-binding transcription factor binding
  evidence_type: IPI
  original_reference_id: PMID:7539918
  qualifier: enables
  review:
    summary: >-
      RNA polymerase II-specific DNA-binding transcription factor binding is a supported molecular interaction
      function for ARNT.
    action: ACCEPT
    reason: >-
      ARNT is the common dimerization partner for AHR/HIF-family DNA-binding transcription factors. Specific
      transcription-factor binding and AHR-binding terms are more informative than generic protein binding.
    supported_by:
    - *id001
    - *id002
    - *id015
    - *id012
- term:
    id: GO:0061629
    label: RNA polymerase II-specific DNA-binding transcription factor binding
  evidence_type: IPI
  original_reference_id: PMID:9079689
  qualifier: enables
  review:
    summary: >-
      RNA polymerase II-specific DNA-binding transcription factor binding is a supported molecular interaction
      function for ARNT.
    action: ACCEPT
    reason: >-
      ARNT is the common dimerization partner for AHR/HIF-family DNA-binding transcription factors. Specific
      transcription-factor binding and AHR-binding terms are more informative than generic protein binding.
    supported_by:
    - *id001
    - *id002
    - *id015
    - *id012
- term:
    id: GO:0061629
    label: RNA polymerase II-specific DNA-binding transcription factor binding
  evidence_type: IPI
  original_reference_id: PMID:10692439
  qualifier: enables
  review:
    summary: >-
      RNA polymerase II-specific DNA-binding transcription factor binding is a supported molecular interaction
      function for ARNT.
    action: ACCEPT
    reason: >-
      ARNT is the common dimerization partner for AHR/HIF-family DNA-binding transcription factors. Specific
      transcription-factor binding and AHR-binding terms are more informative than generic protein binding.
    supported_by:
    - *id001
    - *id002
    - *id015
    - *id012
- term:
    id: GO:0000987
    label: cis-regulatory region sequence-specific DNA binding
  evidence_type: IDA
  original_reference_id: PMID:23275542
  qualifier: enables
  review:
    summary: >-
      cis-regulatory region sequence-specific DNA binding is true but less specific than the supported
      Pol II cis-regulatory DNA-binding role.
    action: MODIFY
    reason: >-
      The primary evidence concerns ARNT-containing AHR/HIF transcription factor complexes binding DRE/XRE
      or HRE cis-regulatory elements. The annotation should use the Pol II cis-regulatory DNA-binding
      term rather than a generic sequence-specific DNA-binding term.
    proposed_replacement_terms:
    - id: GO:0000978
      label: RNA polymerase II cis-regulatory region sequence-specific DNA binding
    supported_by: *id009
- term:
    id: GO:0043565
    label: sequence-specific DNA binding
  evidence_type: IDA
  original_reference_id: PMID:7539918
  qualifier: enables
  review:
    summary: >-
      sequence-specific DNA binding is true but less specific than the supported Pol II cis-regulatory
      DNA-binding role.
    action: MODIFY
    reason: >-
      The primary evidence concerns ARNT-containing AHR/HIF transcription factor complexes binding DRE/XRE
      or HRE cis-regulatory elements. The annotation should use the Pol II cis-regulatory DNA-binding
      term rather than a generic sequence-specific DNA-binding term.
    proposed_replacement_terms:
    - id: GO:0000978
      label: RNA polymerase II cis-regulatory region sequence-specific DNA binding
    supported_by: *id009
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IDA
  original_reference_id: PMID:7539918
  qualifier: involved_in
  review:
    summary: >-
      positive regulation of transcription by RNA polymerase II is supported by ARNT-containing AHR and
      HIF transcriptional regulatory complexes.
    action: ACCEPT
    reason: >-
      ARNT-containing heterodimers activate and regulate RNA polymerase II target genes in hypoxia and
      xenobiotic-response pathways. This is a central biological role of the protein.
    supported_by:
    - *id003
    - *id004
    - *id005
    - *id001
    - *id002
- term:
    id: GO:0000785
    label: chromatin
  evidence_type: ISA
  original_reference_id: GO_REF:0000113
  qualifier: located_in
  review:
    summary: >-
      Chromatin localization is consistent with ARNT as a DNA-binding transcription factor subunit.
    action: ACCEPT
    reason: >-
      AHR-ARNT and HIF-alpha:ARNT complexes bind regulatory DNA in chromatin to regulate Pol II transcription.
    supported_by:
    - reference_id: PMID:30429208
      supporting_text: >-
        both HIF‐α isoforms bind chromatin in a stoichiometric ratio with HIF‐1β
    - reference_id: PMID:28396409
      supporting_text: >-
        mammalian AHR-ARNT heterodimer in complex with the DRE
- term:
    id: GO:0000981
    label: DNA-binding transcription factor activity, RNA polymerase II-specific
  evidence_type: ISA
  original_reference_id: GO_REF:0000113
  qualifier: enables
  review:
    summary: >-
      DNA-binding transcription factor activity, RNA polymerase II-specific captures the transcription-factor
      activity of ARNT-containing RNA polymerase II regulatory complexes.
    action: ACCEPT
    reason: >-
      The activity is best interpreted as the activity of ARNT-containing heterodimers. ARNT contributes
      DNA-binding and PAS-dimerization surfaces to AHR/HIF complexes that regulate Pol II target genes.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id012
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:16181639
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: *id011
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:28396409
  qualifier: enables
  review:
    summary: >-
      The interaction evidence is real, but the GO term protein binding is uninformative for ARNT.
    action: MODIFY
    reason: >-
      For ARNT, these interaction papers support bHLH-PAS transcription factor heterodimerization or AHR
      binding rather than a generic protein-binding molecular function. Replace with an informative dimerization
      or AHR-binding term where appropriate.
    proposed_replacement_terms: *id018
    supported_by:
    - *id012
    - *id013
    - *id006
- term:
    id: GO:0042803
    label: protein homodimerization activity
  evidence_type: IDA
  original_reference_id: PMID:16181639
  qualifier: enables
  review:
    summary: >-
      ARNT PAS-B homodimerization is experimentally observed but is not the main physiological ARNT function.
    action: KEEP_AS_NON_CORE
    reason: >-
      The cited structural study reports concentration-dependent self-association of the ARNT PAS-B domain,
      but the established cellular functions are heterodimeric AHR/HIF-family transcription complexes.
    supported_by:
    - reference_id: PMID:16181639
      supporting_text: >-
        this domain self-associates in a concentration-dependent manner
    - reference_id: PMID:16181639
      supporting_text: >-
        the interface used in this homodimeric complex is very similar to that used in the formation of
        heterodimer
- term:
    id: GO:0046982
    label: protein heterodimerization activity
  evidence_type: IDA
  original_reference_id: PMID:16181639
  qualifier: enables
  review:
    summary: >-
      ARNT heterodimerization is a core molecular function.
    action: ACCEPT
    reason: >-
      Multiple structural and functional studies show ARNT forming heterodimers with AHR and HIF-alpha
      proteins through bHLH-PAS/PAS-B interfaces; these heterodimers are the active transcriptional regulatory
      complexes.
    supported_by:
    - *id012
    - *id013
    - *id001
    - *id002
- term:
    id: GO:1990837
    label: sequence-specific double-stranded DNA binding
  evidence_type: IDA
  original_reference_id: PMID:28396409
  qualifier: enables
  review:
    summary: >-
      sequence-specific double-stranded DNA binding is consistent with ARNT-containing AHR and HIF transcription
      factor complexes binding regulatory DNA.
    action: ACCEPT
    reason: >-
      ARNT is a bHLH-PAS transcription factor subunit. Primary AHR and HIF studies show ARNT-containing
      heterodimers binding DRE/XRE or HRE-like regulatory DNA and activating transcription.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0090575
    label: RNA polymerase II transcription regulator complex
  evidence_type: IDA
  original_reference_id: PMID:7539918
  qualifier: part_of
  review:
    summary: >-
      ARNT is part of RNA polymerase II transcription regulator complexes.
    action: ACCEPT
    reason: >-
      HIF and AHR transcription complexes contain ARNT and regulate Pol II target genes through HRE/DRE
      regulatory elements.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0090575
    label: RNA polymerase II transcription regulator complex
  evidence_type: IDA
  original_reference_id: PMID:8756616
  qualifier: part_of
  review:
    summary: >-
      ARNT is part of RNA polymerase II transcription regulator complexes.
    action: ACCEPT
    reason: >-
      HIF and AHR transcription complexes contain ARNT and regulate Pol II target genes through HRE/DRE
      regulatory elements.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id003
- term:
    id: GO:0000981
    label: DNA-binding transcription factor activity, RNA polymerase II-specific
  evidence_type: IDA
  original_reference_id: PMID:7539918
  qualifier: contributes_to
  review:
    summary: >-
      DNA-binding transcription factor activity, RNA polymerase II-specific captures the transcription-factor
      activity of ARNT-containing RNA polymerase II regulatory complexes.
    action: ACCEPT
    reason: >-
      The activity is best interpreted as the activity of ARNT-containing heterodimers. ARNT contributes
      DNA-binding and PAS-dimerization surfaces to AHR/HIF complexes that regulate Pol II target genes.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id012
- term:
    id: GO:0000981
    label: DNA-binding transcription factor activity, RNA polymerase II-specific
  evidence_type: IDA
  original_reference_id: PMID:8756616
  qualifier: contributes_to
  review:
    summary: >-
      DNA-binding transcription factor activity, RNA polymerase II-specific captures the transcription-factor
      activity of ARNT-containing RNA polymerase II regulatory complexes.
    action: ACCEPT
    reason: >-
      The activity is best interpreted as the activity of ARNT-containing heterodimers. ARNT contributes
      DNA-binding and PAS-dimerization surfaces to AHR/HIF complexes that regulate Pol II target genes.
    supported_by:
    - *id006
    - *id007
    - *id008
    - *id012
- term:
    id: GO:0001666
    label: response to hypoxia
  evidence_type: IDA
  original_reference_id: PMID:8756616
  qualifier: involved_in
  review:
    summary: >-
      response to hypoxia is supported through ARNT/HIF transcriptional response to low oxygen.
    action: ACCEPT
    reason: >-
      ARNT is HIF-1 beta, the constitutive dimerization partner for HIF-alpha proteins. Loss of ARNT/HIF-1
      beta disrupts hypoxia-inducible VEGF expression, and HIF-alpha:ARNT complexes drive hypoxia transcriptional
      programs.
    supported_by: *id014
- term:
    id: GO:0001938
    label: positive regulation of endothelial cell proliferation
  evidence_type: IC
  original_reference_id: PMID:8756616
  qualifier: involved_in
  review:
    summary: >-
      Endothelial proliferation is downstream of VEGF induction and too indirect for ARNT.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      PMID:8756616 supports HIF-1-dependent VEGF transcription and loss of hypoxic VEGF induction in ARNT-deficient
      cells. Endothelial proliferation is a downstream biological consequence, not a direct ARNT gene-product
      function.
    supported_by:
    - reference_id: PMID:8756616
      supporting_text: >-
        These findings implicate HIF-1 in the activation of VEGF transcription in hypoxic cells.
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:8089148
  qualifier: located_in
  review:
    summary: >-
      nucleus is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
- term:
    id: GO:0010575
    label: positive regulation of vascular endothelial growth factor production
  evidence_type: IDA
  original_reference_id: PMID:8756616
  qualifier: involved_in
  review:
    summary: >-
      Positive regulation of VEGF production is supported as a downstream HIF-1 transcriptional output.
    action: KEEP_AS_NON_CORE
    reason: >-
      ARNT/HIF-1 beta is required for hypoxia-induced VEGF expression, but this is a pathway output rather
      than ARNT molecular core function.
    supported_by:
    - reference_id: PMID:8756616
      supporting_text: >-
        VEGF mRNA was not induced by hypoxia in mutant cells that do not express the HIF-1beta (ARNT)
        subunit.
    - reference_id: PMID:8756616
      supporting_text: >-
        These findings implicate HIF-1 in the activation of VEGF transcription in hypoxic cells.
- term:
    id: GO:0017162
    label: aryl hydrocarbon receptor binding
  evidence_type: IPI
  original_reference_id: PMID:9079689
  qualifier: enables
  review:
    summary: >-
      aryl hydrocarbon receptor binding is a supported molecular interaction function for ARNT.
    action: ACCEPT
    reason: >-
      ARNT is the common dimerization partner for AHR/HIF-family DNA-binding transcription factors. Specific
      transcription-factor binding and AHR-binding terms are more informative than generic protein binding.
    supported_by:
    - *id001
    - *id002
    - *id015
    - *id012
- term:
    id: GO:0030949
    label: positive regulation of vascular endothelial growth factor receptor signaling pathway
  evidence_type: IC
  original_reference_id: PMID:8756616
  qualifier: involved_in
  review:
    summary: >-
      VEGF receptor signaling is a downstream inference from VEGF production and should not be asserted
      for ARNT.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      The experimental evidence supports ARNT/HIF-dependent VEGF transcription, not direct positive regulation
      of VEGF receptor signaling by ARNT.
    supported_by:
    - reference_id: PMID:8756616
      supporting_text: >-
        These findings implicate HIF-1 in the activation of VEGF transcription in hypoxic cells.
- term:
    id: GO:0045648
    label: positive regulation of erythrocyte differentiation
  evidence_type: IC
  original_reference_id: PMID:1448077
  qualifier: involved_in
  review:
    summary: >-
      positive regulation of erythrocyte differentiation is an indirect downstream annotation from early
      hypoxia/EPO enhancer work.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      PMID:1448077 identifies a hypoxia-inducible enhancer-binding factor for erythropoietin regulation
      but does not specifically establish ARNT as directly regulating erythrocyte differentiation or hormone
      biosynthesis. Modern ARNT annotations should emphasize HIF/AHR transcription-factor activity and
      hypoxia response.
    supported_by:
    - reference_id: PMID:1448077
      supporting_text: >-
        We have identified a 50-nucleotide enhancer from the human erythropoietin gene 3'-flanking sequence
        which can mediate a sevenfold transcriptional induction in response to hypoxia
    - reference_id: PMID:1448077
      supporting_text: >-
        Factor binding was induced by hypoxia
- term:
    id: GO:0046886
    label: positive regulation of hormone biosynthetic process
  evidence_type: IDA
  original_reference_id: PMID:1448077
  qualifier: involved_in
  review:
    summary: >-
      positive regulation of hormone biosynthetic process is an indirect downstream annotation from early
      hypoxia/EPO enhancer work.
    action: MARK_AS_OVER_ANNOTATED
    reason: >-
      PMID:1448077 identifies a hypoxia-inducible enhancer-binding factor for erythropoietin regulation
      but does not specifically establish ARNT as directly regulating erythrocyte differentiation or hormone
      biosynthesis. Modern ARNT annotations should emphasize HIF/AHR transcription-factor activity and
      hypoxia response.
    supported_by:
    - reference_id: PMID:1448077
      supporting_text: >-
        We have identified a 50-nucleotide enhancer from the human erythropoietin gene 3'-flanking sequence
        which can mediate a sevenfold transcriptional induction in response to hypoxia
    - reference_id: PMID:1448077
      supporting_text: >-
        Factor binding was induced by hypoxia
- term:
    id: GO:0046982
    label: protein heterodimerization activity
  evidence_type: IPI
  original_reference_id: PMID:9079689
  qualifier: enables
  review:
    summary: >-
      ARNT heterodimerization is a core molecular function.
    action: ACCEPT
    reason: >-
      Multiple structural and functional studies show ARNT forming heterodimers with AHR and HIF-alpha
      proteins through bHLH-PAS/PAS-B interfaces; these heterodimers are the active transcriptional regulatory
      complexes.
    supported_by:
    - *id012
    - *id013
    - *id001
    - *id002
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: TAS
  original_reference_id: PMID:10777486
  qualifier: enables
  review:
    summary: >-
      The broad DNA-binding transcription factor annotation is directionally correct but should be represented
      by RNA polymerase II-specific DNA-binding transcription factor terms.
    action: MODIFY
    reason: >-
      ARNT is not a generic transcription factor; its curated role is as a bHLH-PAS subunit of RNA polymerase
      II regulatory complexes that bind defined cis-regulatory DNA elements. A more specific Pol II DNA-binding
      transcription factor term is preferable.
    proposed_replacement_terms: *id017
    supported_by: *id009
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: TAS
  original_reference_id: PMID:1317062
  qualifier: enables
  review:
    summary: >-
      The broad DNA-binding transcription factor annotation is directionally correct but should be represented
      by RNA polymerase II-specific DNA-binding transcription factor terms.
    action: MODIFY
    reason: >-
      ARNT is not a generic transcription factor; its curated role is as a bHLH-PAS subunit of RNA polymerase
      II regulatory complexes that bind defined cis-regulatory DNA elements. A more specific Pol II DNA-binding
      transcription factor term is preferable.
    proposed_replacement_terms: *id017
    supported_by: *id009
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: TAS
  original_reference_id: PMID:1317062
  qualifier: located_in
  review:
    summary: >-
      nucleus is a supported nuclear localization for ARNT.
    action: ACCEPT
    reason: >-
      ARNT functions in nuclear transcription factor complexes and is reported as nuclear by UniProt,
      primary AHR/HIF studies, Reactome complex events, and HPA-derived nucleoplasm annotations.
    supported_by:
    - reference_id: file:human/ARNT/ARNT-uniprot.txt
      supporting_text: >-
        SUBCELLULAR LOCATION: Nucleus
    - reference_id: PMID:1317062
      supporting_text: >-
        Arnt and the ligand-binding subunit of the receptor were extracted as a complex from the nuclei
        of cells treated with ligand.
    - reference_id: PMID:34521881
      supporting_text: >-
        ARNT is a nuclear protein that acts as dimerization partner for several transcription factors
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:0000052
  title: Gene Ontology annotation based on curation of immunofluorescence data
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to orthologs using
    Ensembl Compara
  findings: []
- id: GO_REF:0000108
  title: Automatic assignment of GO terms using logical inference, based on on inter-ontology links
  findings: []
- id: GO_REF:0000113
  title: Gene Ontology annotation of human sequence-specific DNA binding transcription factors
    (DbTFs) based on the TFClass database
  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:10085255
  title: 'Induction and nuclear translocation of hypoxia-inducible factor-1 (HIF-1): heterodimerization
    with ARNT is not necessary for nuclear accumulation of HIF-1alpha.'
  findings: []
- id: PMID:10395741
  title: Interactions of nuclear receptor coactivator/corepressor proteins with the aryl hydrocarbon
    receptor complex.
  findings: []
- id: PMID:10692439
  title: Cardiovascular basic helix loop helix factor 1, a novel transcriptional repressor expressed
    preferentially in the developing and adult cardiovascular system.
  findings: []
- id: PMID:10777486
  title: Role of hypoxia-inducible factor-1 in transcriptional activation of ceruloplasmin by iron
    deficiency.
  findings: []
- id: PMID:11018023
  title: CLIF, a novel cycle-like factor, regulates the circadian oscillation of plasminogen
    activator inhibitor-1 gene expression.
  findings: []
- id: PMID:1317062
  title: Identification of the Ah receptor nuclear translocator protein (Arnt) as a component of the
    DNA binding form of the Ah receptor.
  findings: []
- id: PMID:1448077
  title: A nuclear factor induced by hypoxia via de novo protein synthesis binds to the human
    erythropoietin gene enhancer at a site required for transcriptional activation.
  findings: []
- id: PMID:14668441
  title: Structural basis for PAS domain heterodimerization in the basic helix--loop--helix-PAS
    transcription factor hypoxia-inducible factor.
  findings: []
- id: PMID:16181639
  title: 'Structural basis of ARNT PAS-B dimerization: use of a common beta-sheet interface for hetero-
    and homodimerization.'
  findings: []
- id: PMID:19129502
  title: Artificial ligand binding within the HIF2alpha PAS-B domain of the HIF2 transcription
    factor.
  findings: []
- id: PMID:20562859
  title: Network organization of the human autophagy system.
  findings: []
- id: PMID:20603618
  title: RKTG inhibits angiogenesis by suppressing MAPK-mediated autocrine VEGF signaling and is
    downregulated in clear-cell renal cell carcinoma.
  findings: []
- id: PMID:20932347
  title: Increased accumulation of hypoxia-inducible factor-1α with reduced transcriptional activity
    mediates the antitumor effect of triptolide.
  findings: []
- id: PMID:21620138
  title: Pyruvate kinase M2 is a PHD3-stimulated coactivator for hypoxia-inducible factor 1.
  findings: []
- id: PMID:23033253
  title: Identification of Cys255 in HIF-1α as a novel site for development of covalent inhibitors
    of HIF-1α/ARNT PasB domain protein-protein interaction.
  findings: []
- id: PMID:23275542
  title: 2,3,7,8-Tetrachlorodibenzo-p-dioxin poly(ADP-ribose) polymerase (TiPARP, ARTD14) is a
    mono-ADP-ribosyltransferase and repressor of aryl hydrocarbon receptor transactivation.
  findings: []
- id: PMID:23434853
  title: Allosteric inhibition of hypoxia inducible factor-2 with small molecules.
  findings: []
- id: PMID:24434214
  title: Cbx4 governs HIF-1α to potentiate angiogenesis of hepatocellular carcinoma by its SUMO E3
    ligase activity.
  findings: []
- id: PMID:24981860
  title: Human-chromatin-related protein interactions identify a demethylase complex required for
    chromosome segregation.
  findings: []
- id: PMID:28396409
  title: Structural hierarchy controlling dimerization and target DNA recognition in the AHR
    transcriptional complex.
  findings: []
- id: PMID:28514442
  title: Architecture of the human interactome defines protein communities and disease networks.
  findings: []
- id: PMID:28602820
  title: Structural Basis for Aryl Hydrocarbon Receptor-Mediated Gene Activation.
  findings: []
- id: PMID:29454749
  title: Microbiota-Derived Indole Metabolites Promote Human and Murine Intestinal Homeostasis
    through Regulation of Interleukin-10 Receptor.
  findings: []
- id: PMID:30429208
  title: 'Inherent DNA-binding specificities of the HIF-1α and HIF-2α transcription factors in chromatin.'
  findings: []
- id: PMID:33961781
  title: Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.
  findings: []
- id: PMID:34521881
  title: The role of DNA-binding and ARNT dimerization on the nucleo-cytoplasmic translocation of
    the aryl hydrocarbon receptor.
  findings: []
- id: PMID:7539918
  title: Hypoxia-inducible factor 1 is a basic-helix-loop-helix-PAS heterodimer regulated by
    cellular O2 tension.
  findings: []
- id: PMID:8089148
  title: Transcriptional regulation of genes encoding glycolytic enzymes by hypoxia-inducible factor
    1.
  findings: []
- id: PMID:8756616
  title: Activation of vascular endothelial growth factor gene transcription by hypoxia-inducible
    factor 1.
  findings: []
- id: PMID:9079689
  title: Characterization of a subset of the basic-helix-loop-helix-PAS superfamily that interacts
    with components of the dioxin signaling pathway.
  findings: []
- id: PMID:9704006
  title: Transcriptionally active heterodimer formation of an Arnt-like PAS protein, Arnt3, with
    HIF-1a, HLF, and clock.
  findings: []
- id: Reactome:R-HSA-1234167
  title: Formation of HIF:CBP:p300 complex at promoters
  findings: []
- id: Reactome:R-HSA-1234171
  title: HIF-alpha binds ARNT (HIF1-beta) forming HIF-alpha:ARNT
  findings: []
- id: Reactome:R-HSA-8936851
  title: AHRR binds ARNT
  findings: []
- id: Reactome:R-HSA-8937144
  title: Aryl hydrocarbon receptor signalling
  findings: []
- id: Reactome:R-HSA-8937177
  title: AHR:TCDD binds ARNT
  findings: []
- id: Reactome:R-HSA-9634850
  title: NPAS4 binds ARNT
  findings: []
- id: file:human/ARNT/ARNT-uniprot.txt
  title: UniProt text export for ARNT (P27540)
  findings:
  - statement: UniProt summarizes ARNT as a nuclear bHLH-PAS partner for AHR and HIF-family
      transcription factor complexes.
- id: file:projects/PROTEOSTASIS/reports/pn_projection/pn_projected_annotations.tsv
  title: Proteostasis PN projection report row for ARNT
  findings:
  - statement: The PN projection suggests GO:1990756 for ARNT from a Cul4A/Cul4B substrate adaptor
      group, but this review does not accept the propagation for ARNT without direct adaptor
      evidence.
- id: file:projects/PROTEOSTASIS/mappings/ubiquitin_proteasome_system.yaml
  title: Proteostasis UPS mapping YAML
  findings:
  - statement: The specific AHR / ARNT / TBL3 complex type/subtype nodes are curated as no_mapping,
      indicating that gene-level propagation from those narrower labels requires caution.
- id: file:human/ARNT/ARNT-deep-research-falcon.md
  title: Falcon deep research report for ARNT
  findings:
  - statement: Falcon supports ARNT as a heterodimeric transcription-factor scaffold/partner for AHR
      and HIF-alpha proteins rather than an enzyme, transporter, or proteostasis adaptor.
    supporting_text: ARNT functions primarily as a **heterodimeric transcription-factor
      scaffold/partner**, enabling DNA binding and transcriptional activation by AHR and HIF-α
      proteins rather than acting as an enzyme or transporter.
core_functions:
- description: >-
    ARNT contributes to sequence-specific RNA polymerase II transcription factor activity as the nuclear
    bHLH-PAS beta subunit of HIF-alpha:ARNT and AHR:ARNT complexes. These complexes bind hypoxia response
    elements and xenobiotic/dioxin response elements in regulatory DNA and control hypoxia-adaptive and
    xenobiotic-response transcriptional programs.
  contributes_to_molecular_function:
    id: GO:0000981
    label: DNA-binding transcription factor activity, RNA polymerase II-specific
  directly_involved_in:
  - id: GO:0006357
    label: regulation of transcription by RNA polymerase II
  - id: GO:0001666
    label: response to hypoxia
  - id: GO:0006805
    label: xenobiotic metabolic process
  locations:
  - id: GO:0005634
    label: nucleus
  in_complex:
    id: GO:0090575
    label: RNA polymerase II transcription regulator complex
  supported_by:
  - *id006
  - *id007
  - *id008
  - *id003
  - *id004
  - *id001
  - *id002
  - reference_id: file:human/ARNT/ARNT-deep-research-falcon.md
    supporting_text: >-
      ARNT functions primarily as a **heterodimeric transcription-factor scaffold/partner**, enabling
      DNA binding and transcriptional activation by AHR and HIF-α proteins rather than acting as an enzyme
      or transporter.
- description: >-
    ARNT provides partner-specific bHLH-PAS/PAS-B dimerization surfaces for AHR, HIF1A, EPAS1, and related
    bHLH-PAS transcription factors. Heterodimer formation is required for stable DNA-binding transcription
    complexes and is the central molecular interaction mode for ARNT.
  molecular_function:
    id: GO:0046982
    label: protein heterodimerization activity
  directly_involved_in:
  - id: GO:0006357
    label: regulation of transcription by RNA polymerase II
  locations:
  - id: GO:0005634
    label: nucleus
  supported_by:
  - *id012
  - *id013
  - reference_id: PMID:23033253
    supporting_text: >-
      Biophysical characterization of the interaction between PasB domains of HIF-1α and ARNT revealed
      that covalent binding of COMPOUND 5 to Cys255 reduced binding affinity between HIF-1α and ARNT PasB
      domains approximately 10-fold.
- description: >-
    ARNT participates in the AHR transcriptional complex by binding AHR and forming a DRE/XRE-binding
    heterodimer that regulates xenobiotic-response gene expression. This role is distinct from the PN-projected
    Cul4A/Cul4B substrate adaptor activity, which is not accepted here for ARNT.
  molecular_function:
    id: GO:0017162
    label: aryl hydrocarbon receptor binding
  directly_involved_in:
  - id: GO:0006805
    label: xenobiotic metabolic process
  - id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  locations:
  - id: GO:0005634
    label: nucleus
  in_complex:
    id: GO:0034753
    label: nuclear aryl hydrocarbon receptor complex
  supported_by:
  - *id001
  - *id002
  - *id015
  - reference_id: file:projects/PROTEOSTASIS/reports/pn_projection/pn_projected_annotations.tsv
    supporting_text: >-
      ARNT ... GO:1990756 ... ubiquitin-like ligase-substrate adaptor activity ... new_to_goa ... Ubiquitin
      Proteasome System|E3 ubiquitin and UBL ligases|Cul4A/Cul4B substrate adaptor|AHR / ARNT / TBL3 complex|PAS
  - reference_id: file:projects/PROTEOSTASIS/mappings/ubiquitin_proteasome_system.yaml
    supporting_text: >-
      Reviewed as a narrower substrate-receptor, adaptor, domain, or family subdivision already covered
      by the curated parent adaptor/receptor mapping. No additional direct GO mapping is needed at this
      node.
proposed_new_terms: []
suggested_questions:
- question: >-
    Does any primary literature directly show ARNT functioning as a Cul4A/Cul4B ubiquitin-like ligase
    substrate adaptor, or is the PN workbook row reflecting AHR/ARNT/TBL3 complex context rather than
    ARNT molecular activity?
- question: >-
    Should generic ARNT protein-binding annotations from large-scale interactome studies be replaced systematically
    with partner-specific transcription factor binding or heterodimerization terms where the original
    evidence supports that interpretation?
- question: >-
    For downstream HIF outputs such as VEGF production, glycolytic gene expression, and erythropoietin-related
    phenotypes, which annotations should remain on ARNT as pathway-level non-core annotations rather than
    direct core gene-product functions?
suggested_experiments:
- hypothesis: ARNT does not directly act as a CRL4 substrate adaptor.
  description: >-
    Test epitope-tagged ARNT for stable association with DDB1, CUL4A/CUL4B, RBX1, DDA1, and candidate
    CRL4 substrates under conditions that preserve known AHR/HIF complexes. Compare with positive-control
    DCAF substrate receptors and require substrate ubiquitination or degradation evidence before assigning
    GO:1990756.
  experiment_type: co-immunoprecipitation and ubiquitination assay
- hypothesis: ARNT protein-binding annotations can be converted to informative transcription-factor
    dimerization annotations.
  description: >-
    Re-curate ARNT interaction papers by partner class (AHR, HIF1A, EPAS1, NPAS/SIM factors, co-regulators)
    and validate whether each supports GO:0046982, GO:0061629, or GO:0017162 instead of generic GO:0005515.
  experiment_type: literature curation audit