Seroatlas · Human Serome Atlas

CIAO3

Cytosolic iron-sulfur assembly component 3

Also known as: CIAO3_HUMAN, FLJ21988, HPRN, IOP1, NAR1, NARFL, PRN

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
Q9H6Q4
Gene
CIAO3
Ensembl
ENSG00000103245
Chromosome
16
Canonical length
476 aa
Protein class
Predicted intracellular proteins
Subcellular location
Plasma membrane,Cytosol

OverviewNCBI Gene

Predicted to enable 4 iron, 4 sulfur cluster binding activity and metal ion binding activity. Involved in several processes, including intracellular oxygen homeostasis; iron-sulfur cluster assembly; and response to hypoxia. Part of cytosolic [4Fe-4S] assembly targeting complex. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

476 residues, UniProt reviewed canonical sequence.

>Q9H6Q4|CIAO3
     1  MASPFSGALQ LTDLDDFIGP SQECIKPVKV EKRAGSGVAK IRIEDDGSYF QINQDGGTRR
    61  LEKAKVSLND CLACSGCITS AETVLITQQS HEELKKVLDA NKMAAPSQQR LVVVSVSPQS
   121  RASLAARFQL NPTDTARKLT SFFKKIGVHF VFDTAFSRHF SLLESQREFV RRFRGQADCR
   181  QALPLLASAC PGWICYAEKT HGSFILPHIS TARSPQQVMG SLVKDFFAQQ QHLTPDKIYH
   241  VTVMPCYDKK LEASRPDFFN QEHQTRDVDC VLTTGEVFRL LEEEGVSLPD LEPAPLDSLC
   301  SGASAEEPTS HRGGGSGGYL EHVFRHAARE LFGIHVAEVT YKPLRNKDFQ EVTLEKEGQV
   361  LLHFAMAYGF RNIQNLVQRL KRGRCPYHYV EVMACPSGCL NGGGQLQAPD RPSRELLQHV
   421  ERLYGMVRAE APEDAPGVQE LYTHWLQGTD SECAGRLLHT QYHAVEKAST GLGIRW

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CIAO3 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.28
Highest tissue expression
24 nTPM

Expression across tissuesHPA

Tissue

  • cerebellum: 24 nTPM
  • cerebral cortex: 24 nTPM
  • liver: 22 nTPM
  • heart muscle: 22 nTPM
  • kidney: 21 nTPM
  • hippocampal formation: 21 nTPM

Single-cell type

  • retinal horizontal cells: 38 nCPM
  • epididymal principal cells: 35 nCPM
  • hematopoietic stem cells: 32 nCPM
  • esophageal basal cells: 28 nCPM
  • enterocytes: 27 nCPM
  • cytotrophoblasts: 26 nCPM

Immune cell

  • NK-cell: 16 nTPM
  • memory B-cell: 15 nTPM
  • naive CD8 T-cell: 12 nTPM
  • myeloid DC: 12 nTPM
  • T-reg: 12 nTPM
  • non-classical monocyte: 12 nTPM

Brain region

  • cerebral cortex: 21 nTPM
  • pons: 20 nTPM
  • basal ganglia: 19 nTPM
  • hippocampal formation: 19 nTPM
  • medulla oblongata: 19 nTPM
  • midbrain: 19 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.06
gnomAD pLI
0
DepMap mean gene effect
-1.64
DepMap dependency class
pan

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CIAO3 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CIAO3 as an antibody target. Whether an autoantibody or antibody against CIAO3 could matter depends on whether native CIAO3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CIAO3 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label CIAO3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CIAO3. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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