DNAJC12

UniProt ID: Q9UKB3
Organism: Homo sapiens
Review Status: COMPLETE
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Gene Description

DNAJC12 (also called JDP1) is a small cytosolic "J domain-only" co-chaperone of the DnaJ/Hsp40 (DNAJC) family, consisting of an N-terminal J domain (with the conserved HPD motif) and a C-terminal intrinsically disordered region. As a co-chaperone of the HSP70 family, it binds the cognate Hsp70 chaperone Hsc70 (HSPA8) and, through its J domain, stimulates HSP70 ATPase activity. DNAJC12 is a dedicated chaperone for the biopterin (BH4)-dependent aromatic amino acid hydroxylases, interacting with phenylalanine hydroxylase (PAH), tyrosine hydroxylase (TH) and tryptophan hydroxylases (TPH1, TPH2) and assisting their proper folding and stability. It is diffusely cytoplasmic and is up-regulated by ER stress. Biallelic loss-of-function variants cause autosomal-recessive non-BH4-deficient hyperphenylalaninemia accompanied by dopamine and serotonin deficiency, dystonia/parkinsonism and intellectual disability, a condition treatable with BH4 and neurotransmitter precursors.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0005737 cytoplasm
IBA
GO_REF:0000033 		ACCEPT
Summary: Phylogenetically inferred cytoplasmic localization, consistent with the experimentally established cytoplasmic localization where DNAJC12 acts as an HSP70 co-chaperone for aromatic amino acid hydroxylases.
Reason: Cytoplasm is the experimentally supported site of action of DNAJC12 (PMID:24122553 IDA).
Supporting Evidence:
file:human/DNAJC12/DNAJC12-uniprot.txt
[Isoform a]: Cytoplasm
GO:0005737 cytoplasm
IEA
GO_REF:0000044 		ACCEPT
Summary: Automated subcellular-location transfer of cytoplasmic localization, consistent with the experimentally established compartment.
Reason: Cytoplasm is the experimentally supported compartment of DNAJC12.
Supporting Evidence:
file:human/DNAJC12/DNAJC12-uniprot.txt
[Isoform a]: Cytoplasm
GO:0005515 protein binding
IPI
PMID:28514442
Architecture of the human interactome defines protein commun... 		KEEP AS NON CORE
Summary: Interaction (IntAct WITH tryptophan hydroxylase 1, TPH1, P17752). The bare protein binding term records a real client interaction but is uninformative; it reflects DNAJC12's binding to an aromatic amino acid hydroxylase client.
Reason: Bare protein binding is uninformative; this interaction reflects the hydroxylase-client binding that underlies DNAJC12's chaperone function, captured in the core functions.
Supporting Evidence:
file:human/DNAJC12/DNAJC12-goa.tsv
GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:28514442 UniProtKB:P17752
GO:0005515 protein binding
IPI
PMID:33961781
Dual proteome-scale networks reveal cell-specific remodeling... 		KEEP AS NON CORE
Summary: BioPlex affinity-purification interactome capturing a DNAJC12-TPH1 (P17752) interaction. The bare protein binding term reflects binding to a hydroxylase client.
Reason: Bare protein binding is uninformative; the TPH1 interaction reflects the hydroxylase-client binding underlying DNAJC12's chaperone function.
Supporting Evidence:
file:human/DNAJC12/DNAJC12-goa.tsv
GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:33961781 UniProtKB:P17752
GO:0005515 protein binding
IPI
PMID:24122553
The co-chaperone DNAJC12 binds to Hsc70 and is upregulated b... 		MODIFY
Summary: Immunoaffinity-MS and co-IP showing DNAJC12 interacts with the cognate Hsp70 chaperone Hsc70 (HSPA8, P11142). The bare protein binding term is uninformative; the interaction is specifically with an HSP70-family chaperone.
Reason: Bare protein binding is uninformative. The documented partner is the Hsp70 chaperone Hsc70/HSPA8, so the informative molecular function is Hsp70 protein binding (GO:0030544).
Proposed replacements: Hsp70 protein binding
Supporting Evidence:
PMID:24122553
The most frequently identified partner of DNAJC12 in unstressed cells was Hsc70, a cognate Hsp70 chaperone
GO:0005737 cytoplasm
IDA
PMID:24122553
The co-chaperone DNAJC12 binds to Hsc70 and is upregulated b... 		ACCEPT
Summary: Direct immunofluorescence evidence that DNAJC12 is diffusely distributed in the cytoplasm.
Reason: Cytoplasm is the experimentally established compartment where DNAJC12 acts.
Supporting Evidence:
PMID:24122553
a recombinant DNAJC12 protein is diffusely distributed in the cytoplasm

Core Functions

Cytosolic J-domain co-chaperone of the HSP70 family that binds the cognate Hsp70 chaperone Hsc70 (HSPA8) and stimulates HSP70 ATPase activity via its J-domain HPD motif.

Molecular Function:
Hsp70 protein binding
Cellular Locations:
cytoplasm
Supporting Evidence:
  • PMID:24122553
    The most frequently identified partner of DNAJC12 in unstressed cells was Hsc70, a cognate Hsp70 chaperone
  • PMID:28132689
    DNAJC12 encodes a co-chaperone of the HSP70 family which interacts with PAH, tyrosine hydroxylase, and tryptophan hydroxylase

Dedicated co-chaperone for the biopterin-dependent aromatic amino acid hydroxylases (PAH, TH, TPH1, TPH2), binding these clients and assisting their proper folding and stability; loss of function reduces PAH activity and causes hyperphenylalaninemia.

Molecular Function:
protein-folding chaperone binding
Cellular Locations:
cytoplasm
Supporting Evidence:
  • file:human/DNAJC12/DNAJC12-uniprot.txt
    Probable co-chaperone that participates in the proper folding of biopterin-dependent aromatic amino acid hydroxylases, which include phenylalanine-4-hydroxylase (PAH), tyrosine 3-monooxygenase (TH) and peripheral and neuronal tryptophan hydroxylases (TPH1 and TPH2).
  • PMID:28132689
    PAH enzyme activity was reduced in the presence of DNAJC12 mutations

References

GO_REF:0000033
Annotation inferences using phylogenetic trees
GO_REF:0000044
Gene Ontology annotation through association of InterPro records with GO terms
PMID:24122553
The co-chaperone DNAJC12 binds to Hsc70 and is upregulated by endoplasmic reticulum stress.
  • DNAJC12 binds the cognate Hsp70 chaperone Hsc70 (HSPA8) in unstressed cells and BiP under stress; it is cytoplasmic and up-regulated by ER stress, clarifying its role in regulating Hsp70 function.
PMID:28132689
Biallelic Mutations in DNAJC12 Cause Hyperphenylalaninemia, Dystonia, and Intellectual Disability.
  • DNAJC12 is an HSP70-family co-chaperone that interacts with phenylalanine hydroxylase (PAH), tyrosine hydroxylase and tryptophan hydroxylase; biallelic loss-of-function causes non-BH4-deficient hyperphenylalaninemia with dopamine/serotonin deficiency, dystonia and intellectual disability.
  • PAH enzyme activity is reduced in the presence of DNAJC12 mutations; the J domain (HPD motif) stimulates HSP70 ATPase activity.
PMID:28514442
Architecture of the human interactome defines protein communities and disease networks.
PMID:33961781
Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.
file:human/DNAJC12/DNAJC12-uniprot.txt
UniProt entry Q9UKB3 (DJC12_HUMAN), DnaJ homolog subfamily C member 12 / JDP1
  • Probable co-chaperone participating in proper folding of biopterin-dependent aromatic amino acid hydroxylases (PAH, TH, TPH1, TPH2); interacts with HSPA8/Hsc70; cytoplasmic; loss-of-function causes non-BH4-deficient hyperphenylalaninemia.

Suggested Questions for Experts

Q: Does DNAJC12 recognize a shared structural feature of the aromatic amino acid hydroxylase fold, and how does it coordinate Hsc70 with BH4 cofactor loading during hydroxylase maturation?

Q: Why does DNAJC12 deficiency preferentially manifest as hyperphenylalaninemia with neurotransmitter deficiency, and what determines the variable neurological severity among patients?

Suggested Experiments

Experiment: Reconstitute PAH (and TH/TPH) folding/stability in vitro with DNAJC12, Hsc70 and ATP, comparing wild-type versus HPD-motif and disease (e.g. R72P) mutants to dissect the J-domain-dependent contribution to client maturation.

Experiment: Quantify aromatic amino acid hydroxylase levels and activities, and dopamine/serotonin output, in DNAJC12-knockout neuronal models with and without BH4 supplementation to define the chaperone's role across the hydroxylase family.

📚 Additional Documentation

Notes

(DNAJC12-notes.md)

DNAJC12 (JDP1) research notes

Identity

  • UniProt Q9UKB3 (DJC12_HUMAN), 198 aa. HGNC:28908. Synonym JDP1. "J domain-only" protein:
    N-terminal J domain (14-79, HPD motif) + C-terminal disordered region; no other folded domain.
  • Cytoplasmic (isoform a). NMR structure of J domain (PDB 2CTQ).

Core function: cytosolic HSP70 co-chaperone for aromatic amino acid hydroxylases

  • Co-chaperone that participates in proper folding of biopterin (BH4)-dependent aromatic amino acid
    hydroxylases: PAH, TH (tyrosine 3-monooxygenase), TPH1, TPH2.
    [file:human/DNAJC12/DNAJC12-uniprot.txt "Probable co-chaperone that participates in the proper folding
    of biopterin-dependent aromatic amino acid hydroxylases, which include phenylalanine-4-hydroxylase
    (PAH), tyrosine 3-monooxygenase (TH) and peripheral and neuronal tryptophan hydroxylases (TPH1 and
    TPH2)."]
    PMID:28132689
  • Binds Hsc70 (HSPA8) in unstressed cells; J domain stimulates HSP70 ATPase.
    [PMID:24122553 "The most frequently identified partner of DNAJC12 in unstressed cells was Hsc70, a
    cognate Hsp70 chaperone, whereas in stressed cells, the ER chaperone BiP was frequently associated with
    DNAJC12." ; "These results clarify the role of DNAJC12 in the regulation of Hsp70 function."]
  • J-domain HPD motif stimulates HSP70 ATPase. PMID:28132689
  • PAH enzyme activity reduced in presence of DNAJC12 mutations PMID:28132689

Localization

  • Cytoplasm (IDA PMID:24122553; diffusely distributed in cytoplasm). Up-regulated by ER stress.

Disease

  • Biallelic loss-of-function -> hyperphenylalaninemia, non-BH4-deficient (HPANBH4), with dystonia,
    intellectual disability, dopamine/serotonin deficiency (parkinsonism spectrum). Treatable with BH4 and
    neurotransmitter precursors. PMID:28132689

GOA WITH-partner key

  • P17752 = TPH1 (tryptophan hydroxylase 1) - a hydroxylase client. P11142 = HSPA8/Hsc70.

Review logic

CORE MFs:
- The bare protein binding rows: PMID:24122553 WITH HSPA8 (Hsc70) -> MODIFY to Hsp70 protein binding
(GO:0030544). PMID:28514442 / PMID:33961781 WITH TPH1 -> these capture client (hydroxylase) binding; the
TPH1 interaction reflects the hydroxylase-chaperoning function. Could MODIFY to a client-binding MF but
no specific "aromatic amino acid hydroxylase binding" term; keep as KEEP_AS_NON_CORE or note client.
- No explicit ATPase activator activity / Hsp70 binding term in GOA, so propose Hsp70 protein binding as
core MF (supported by Hsc70 interaction + J-domain ATPase stimulation).
CC:
- cytoplasm (IBA/IEA/IDA): ACCEPT, CORE compartment.

Pn Notes

(DNAJC12-pn-notes.md)

DNAJC12 PN Consistency Notes

  • Generated: 2026-06-18
  • Project: PROTEOSTASIS
  • Scope: PN consistency rereview against local AIGR review and available deep-research artifacts
  • UniProt: Q9UKB3
  • AIGR review status: COMPLETE
  • Review batch: proteostasis-batch-2026-06-07b
  • Batch change status: added

Source Files Checked

Deep Research Files

  • No *-deep-research*.md file found in this gene directory.

AIGR Review Snapshot

  • Description: DNAJC12 (also called JDP1) is a small cytosolic "J domain-only" co-chaperone of the DnaJ/Hsp40 (DNAJC) family, consisting of an N-terminal J domain (with the conserved HPD motif) and a C-terminal intrinsically disordered region. As a co-chaperone of the HSP70 family, it binds the cognate Hsp70 chaperone Hsc70 (HSPA8) and, through its J domain, stimulates HSP70 ATPase activity. DNAJC12 is a dedicated chaperone for the biopterin (BH4)-dependent aromatic amino acid hydroxylases, interacting with phenylalanine hydroxylase (PAH), tyrosine hydroxylase (TH) and tryptophan hydroxylases (TPH1, TPH2) and assisting their proper folding and stability. It is diffusely cytoplasmic and is up-regulated by ER stress. Biallelic loss-of-function variants cause autosomal-recessive non-BH4-deficient hyperphenylalaninemia accompanied by dopamine and serotonin deficiency, dystonia/parkinsonism and intellectual disability, a condition treatable with BH4 and neurotransmitter precursors.
  • Existing/core annotation action counts: ACCEPT: 3; KEEP_AS_NON_CORE: 2; MODIFY: 1

PN Consistency Summary

  • Consistency: Consistent on the J-domain axis. Review, notes, and PN agree DNAJC12 is a cytosolic J-domain-only HSP70 co-chaperone that binds Hsc70/HSPA8 and stimulates HSP70 ATPase. The review MODIFIES the bare GO:0005515 (HSPA8 interaction, PMID:24122553) to GO:0030544, matching the PN projection exactly. No contradiction. The disease-defining specific-client role (chaperone for aromatic amino acid hydroxylases PAH/TH/TPH; PMID:28132689) is captured in the review's core_functions but is outside the single PN row.
  • PN story / NEW pressure: GO:0030544 is verified real and is the right target. GOA currently has only GO:0005515 + GO:0005737, so relative to GOA this is effectively new_to_goa, not more_specific_than_existing_goa as the PN label states (no GO:0031072 parent in GOA) — a minor status-label inaccuracy. The hydroxylase-chaperone biology is the gene's distinctive story but there is no specific "aromatic amino acid hydroxylase binding" GO term; it is appropriately rendered via GO:0051087 (protein-folding chaperone binding) in core_functions. No NEW term warranted.
  • Evidence alignment: PN row carries no titles; review anchors on PMID:24122553 (Hsc70 binding, verified) and PMID:28132689 (HSP70 cochaperone of hydroxylases, verified). No divergence.
  • Verdict: Consistent; PN GO:0030544 defensible and already realized in the review. Recommended edits: [MAP] (minor) correct DNAJC12 projected goa_status from more_specific_than_existing_goa to new_to_goa (GOA lacks the GO:0031072 parent).

Full Consistency Review

  • UniProt: Q9UKB3 (JDP1) · batch: proteostasis-batch-2026-06-07b · review status: COMPLETE
  • PN placement: Cytonuclear proteostasis|Chaperone|HSP70 system|J-domain containing HSP70 cochaperone ; PN-node mapping: type=mapped, scope=ok_for_propagation_to_go, GO:0030544 Hsp70 protein binding (group/class/branch = no_mapping)
  • Consistency: Consistent on the J-domain axis. Review, notes, and PN agree DNAJC12 is a cytosolic J-domain-only HSP70 co-chaperone that binds Hsc70/HSPA8 and stimulates HSP70 ATPase. The review MODIFIES the bare GO:0005515 (HSPA8 interaction, PMID:24122553) to GO:0030544, matching the PN projection exactly. No contradiction. The disease-defining specific-client role (chaperone for aromatic amino acid hydroxylases PAH/TH/TPH; PMID:28132689) is captured in the review's core_functions but is outside the single PN row.
  • PN story / NEW pressure: GO:0030544 is verified real and is the right target. GOA currently has only GO:0005515 + GO:0005737, so relative to GOA this is effectively new_to_goa, not more_specific_than_existing_goa as the PN label states (no GO:0031072 parent in GOA) — a minor status-label inaccuracy. The hydroxylase-chaperone biology is the gene's distinctive story but there is no specific "aromatic amino acid hydroxylase binding" GO term; it is appropriately rendered via GO:0051087 (protein-folding chaperone binding) in core_functions. No NEW term warranted.
  • Mapping strategy: Node mapping is appropriate; DNAJC12 is a genuine HSP70 cochaperone and GO:0030544 is a defensible, suitably narrow propagation. The review already realizes it (MODIFY), so propagation would be confirmatory.
  • Evidence alignment: PN row carries no titles; review anchors on PMID:24122553 (Hsc70 binding, verified) and PMID:28132689 (HSP70 cochaperone of hydroxylases, verified). No divergence.
  • Verdict: Consistent; PN GO:0030544 defensible and already realized in the review. Recommended edits: [MAP] (minor) correct DNAJC12 projected goa_status from more_specific_than_existing_goa to new_to_goa (GOA lacks the GO:0031072 parent).

PN Dossier Context

  • review_batch: proteostasis-batch-2026-06-07b
  • review_yaml: genes/human/DNAJC12/DNAJC12-ai-review.yaml
  • PN workbook rows: 1

PN row 1: Cytonuclear proteostasis | Chaperone | HSP70 system | J-domain containing HSP70 cochaperone

  • UniProt: Q9UKB3
  • In branches: CY
  • PN-node mapping records (path + ancestors):
    • [type] Cytonuclear proteostasis|Chaperone|HSP70 system|J-domain containing HSP70 cochaperone
      status=mapped scope=ok_for_propagation_to_go GO=[GO:0030544 Hsp70 protein binding]
      rationale: In the PN hierarchy, this type denotes J-domain cochaperones assigned to the HSP70 system. Their shared mechanistic role is direct interaction with HSP70-family chaperones, making Hsp70 protein binding the most defensible GO target in the current cache.
    • [group] Cytonuclear proteostasis|Chaperone|HSP70 system
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a broad PN category rather than a specific GO class. The member genes span multiple activities, complexes, or contexts, so propagation from this node would overstate the shared biology; use narrower child or gene-level curations.
    • [class] Cytonuclear proteostasis|Chaperone
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a broad PN category rather than a specific GO class. The member genes span multiple activities, complexes, or contexts, so propagation from this node would overstate the shared biology; use narrower child or gene-level curations.
    • [branch] Cytonuclear proteostasis
      status=no_mapping scope= GO=[]
      rationale: Reviewed as a top-level PN branch. This is a systems/taxonomy umbrella, not a direct GO assertion; narrower child curations carry any propagating GO mappings.

Projected GO annotations (1)

  • GO:0030544 Hsp70 protein binding | scope=ok_for_propagation_to_go | goa_status=more_specific_than_existing_goa | from=Cytonuclear proteostasis|Chaperone|HSP70 system|J-domain containing HSP70 cochaperone

Note

This file is generated from the current PROTEOSTASIS phase-1 dossier and local gene-review artifacts. Edit the source review, PN mapping, or dossier rather than this generated note when correcting the underlying curation.

📄 View Raw YAML

 
id: Q9UKB3
gene_symbol: DNAJC12
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: DNAJC12 (also called JDP1) is a small cytosolic "J domain-only" co-chaperone of the DnaJ/Hsp40 (DNAJC) family, consisting of an N-terminal J domain (with the conserved HPD motif) and a C-terminal intrinsically disordered region. As a co-chaperone of the HSP70 family, it binds the cognate Hsp70 chaperone Hsc70 (HSPA8) and, through its J domain, stimulates HSP70 ATPase activity. DNAJC12 is a dedicated chaperone for the biopterin (BH4)-dependent aromatic amino acid hydroxylases, interacting with phenylalanine hydroxylase (PAH), tyrosine hydroxylase (TH) and tryptophan hydroxylases (TPH1, TPH2) and assisting their proper folding and stability. It is diffusely cytoplasmic and is up-regulated by ER stress. Biallelic loss-of-function variants cause autosomal-recessive non-BH4-deficient hyperphenylalaninemia accompanied by dopamine and serotonin deficiency, dystonia/parkinsonism and intellectual disability, a condition treatable with BH4 and neurotransmitter precursors.
alternative_products:
- name: a (JDP1a)
  id: Q9UKB3-1
- name: B (JDP1b)
  id: Q9UKB3-2
  sequence_note: VSP_001295, VSP_001296
existing_annotations:
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: Phylogenetically inferred cytoplasmic localization, consistent with the experimentally established cytoplasmic localization where DNAJC12 acts as an HSP70 co-chaperone for aromatic amino acid hydroxylases.
    action: ACCEPT
    reason: Cytoplasm is the experimentally supported site of action of DNAJC12 (PMID:24122553 IDA).
    supported_by:
    - reference_id: file:human/DNAJC12/DNAJC12-uniprot.txt
      supporting_text: '[Isoform a]: Cytoplasm'
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: Automated subcellular-location transfer of cytoplasmic localization, consistent with the experimentally established compartment.
    action: ACCEPT
    reason: Cytoplasm is the experimentally supported compartment of DNAJC12.
    supported_by:
    - reference_id: file:human/DNAJC12/DNAJC12-uniprot.txt
      supporting_text: '[Isoform a]: Cytoplasm'
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:28514442
  qualifier: enables
  review:
    summary: Interaction (IntAct WITH tryptophan hydroxylase 1, TPH1, P17752). The bare protein binding term records a real client interaction but is uninformative; it reflects DNAJC12's binding to an aromatic amino acid hydroxylase client.
    action: KEEP_AS_NON_CORE
    reason: Bare protein binding is uninformative; this interaction reflects the hydroxylase-client binding that underlies DNAJC12's chaperone function, captured in the core functions.
    supported_by:
    - reference_id: file:human/DNAJC12/DNAJC12-goa.tsv
      supporting_text: GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:28514442 UniProtKB:P17752
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:33961781
  qualifier: enables
  review:
    summary: BioPlex affinity-purification interactome capturing a DNAJC12-TPH1 (P17752) interaction. The bare protein binding term reflects binding to a hydroxylase client.
    action: KEEP_AS_NON_CORE
    reason: Bare protein binding is uninformative; the TPH1 interaction reflects the hydroxylase-client binding underlying DNAJC12's chaperone function.
    supported_by:
    - reference_id: file:human/DNAJC12/DNAJC12-goa.tsv
      supporting_text: GO:0005515 protein binding molecular_function ECO:0000353 IPI PMID:33961781 UniProtKB:P17752
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:24122553
  qualifier: enables
  review:
    summary: Immunoaffinity-MS and co-IP showing DNAJC12 interacts with the cognate Hsp70 chaperone Hsc70 (HSPA8, P11142). The bare protein binding term is uninformative; the interaction is specifically with an HSP70-family chaperone.
    action: MODIFY
    reason: Bare protein binding is uninformative. The documented partner is the Hsp70 chaperone Hsc70/HSPA8, so the informative molecular function is Hsp70 protein binding (GO:0030544).
    proposed_replacement_terms:
    - id: GO:0030544
      label: Hsp70 protein binding
    supported_by:
    - reference_id: PMID:24122553
      supporting_text: The most frequently identified partner of DNAJC12 in unstressed cells was Hsc70, a cognate Hsp70 chaperone
- term:
    id: GO:0005737
    label: cytoplasm
  evidence_type: IDA
  original_reference_id: PMID:24122553
  qualifier: located_in
  review:
    summary: Direct immunofluorescence evidence that DNAJC12 is diffusely distributed in the cytoplasm.
    action: ACCEPT
    reason: Cytoplasm is the experimentally established compartment where DNAJC12 acts.
    supported_by:
    - reference_id: PMID:24122553
      supporting_text: a recombinant DNAJC12 protein is diffusely distributed in the cytoplasm
references:
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000044
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings: []
- id: PMID:24122553
  title: The co-chaperone DNAJC12 binds to Hsc70 and is upregulated by endoplasmic reticulum stress.
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Cached publication title matches PubMed; body confirms DNAJC12 binds Hsc70 (HSPA8) and is a cytoplasmic stress-upregulated co-chaperone. GOA anchors this PMID to GO:0005737 (cytoplasm, IDA) and GO:0005515, supporting DNAJC12's core J-domain co-chaperone function.
  findings:
  - statement: DNAJC12 binds the cognate Hsp70 chaperone Hsc70 (HSPA8) in unstressed cells and BiP under stress; it is cytoplasmic and up-regulated by ER stress, clarifying its role in regulating Hsp70 function.
    reference_section_type: ABSTRACT
- id: PMID:28132689
  title: Biallelic Mutations in DNAJC12 Cause Hyperphenylalaninemia, Dystonia, and Intellectual Disability.
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: Cached publication title matches PubMed; body confirms DNAJC12 is an HSP70 co-chaperone of the aromatic amino acid hydroxylases (PAH, TH, TPH) whose biallelic loss-of-function causes hyperphenylalaninemia with neurotransmitter deficiency, establishing the gene's in-vivo specific-client chaperone function.
  findings:
  - statement: DNAJC12 is an HSP70-family co-chaperone that interacts with phenylalanine hydroxylase (PAH), tyrosine hydroxylase and tryptophan hydroxylase; biallelic loss-of-function causes non-BH4-deficient hyperphenylalaninemia with dopamine/serotonin deficiency, dystonia and intellectual disability.
    reference_section_type: ABSTRACT
  - statement: PAH enzyme activity is reduced in the presence of DNAJC12 mutations; the J domain (HPD motif) stimulates HSP70 ATPase activity.
    reference_section_type: RESULTS
- id: PMID:28514442
  title: Architecture of the human interactome defines protein communities and disease networks.
  findings: []
- id: PMID:33961781
  title: Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.
  findings: []
- id: file:human/DNAJC12/DNAJC12-uniprot.txt
  title: UniProt entry Q9UKB3 (DJC12_HUMAN), DnaJ homolog subfamily C member 12 / JDP1
  findings:
  - statement: Probable co-chaperone participating in proper folding of biopterin-dependent aromatic amino acid hydroxylases (PAH, TH, TPH1, TPH2); interacts with HSPA8/Hsc70; cytoplasmic; loss-of-function causes non-BH4-deficient hyperphenylalaninemia.
    reference_section_type: OTHER
core_functions:
- description: Cytosolic J-domain co-chaperone of the HSP70 family that binds the cognate Hsp70 chaperone Hsc70 (HSPA8) and stimulates HSP70 ATPase activity via its J-domain HPD motif.
  molecular_function:
    id: GO:0030544
    label: Hsp70 protein binding
  locations:
  - id: GO:0005737
    label: cytoplasm
  supported_by:
  - reference_id: PMID:24122553
    supporting_text: The most frequently identified partner of DNAJC12 in unstressed cells was Hsc70, a cognate Hsp70 chaperone
  - reference_id: PMID:28132689
    supporting_text: DNAJC12 encodes a co-chaperone of the HSP70 family which interacts with PAH, tyrosine hydroxylase, and tryptophan hydroxylase
- description: Dedicated co-chaperone for the biopterin-dependent aromatic amino acid hydroxylases (PAH, TH, TPH1, TPH2), binding these clients and assisting their proper folding and stability; loss of function reduces PAH activity and causes hyperphenylalaninemia.
  molecular_function:
    id: GO:0051087
    label: protein-folding chaperone binding
  locations:
  - id: GO:0005737
    label: cytoplasm
  supported_by:
  - reference_id: file:human/DNAJC12/DNAJC12-uniprot.txt
    supporting_text: Probable co-chaperone that participates in the proper folding of biopterin-dependent aromatic amino acid hydroxylases, which include phenylalanine-4-hydroxylase (PAH), tyrosine 3-monooxygenase (TH) and peripheral and neuronal tryptophan hydroxylases (TPH1 and TPH2).
  - reference_id: PMID:28132689
    supporting_text: PAH enzyme activity was reduced in the presence of DNAJC12 mutations
proposed_new_terms: []
suggested_questions:
- question: Does DNAJC12 recognize a shared structural feature of the aromatic amino acid hydroxylase fold, and how does it coordinate Hsc70 with BH4 cofactor loading during hydroxylase maturation?
- question: Why does DNAJC12 deficiency preferentially manifest as hyperphenylalaninemia with neurotransmitter deficiency, and what determines the variable neurological severity among patients?
suggested_experiments:
- description: Reconstitute PAH (and TH/TPH) folding/stability in vitro with DNAJC12, Hsc70 and ATP, comparing wild-type versus HPD-motif and disease (e.g. R72P) mutants to dissect the J-domain-dependent contribution to client maturation.
- description: Quantify aromatic amino acid hydroxylase levels and activities, and dopamine/serotonin output, in DNAJC12-knockout neuronal models with and without BH4 supplementation to define the chaperone's role across the hydroxylase family.