Seroatlas · Human Serome Atlas

MT-CO3

Cytochrome c oxidase subunit 3

Also known as: CO3, COIII, COX3, COX3_HUMAN, MTCO3

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

Protein identityUniProt · HPA

UniProt accession
P00414
Gene
MT-CO3
Ensembl
ENSG00000198938
Chromosome
MT
Canonical length
261 aa
Protein class
Disease related genes, Enzymes, Human disease related genes, Metabolic proteins, Potential drug targets, Predicted membrane proteins, Transporters

OverviewNCBI Gene

Predicted to contribute to cytochrome-c oxidase activity. Involved in respiratory chain complex IV assembly. Located in mitochondrial membrane. Part of respiratory chain complex IV. Implicated in MELAS syndrome. [provided by Alliance of Genome Resources, Apr 2025]

Canonical amino-acid sequenceUniProt

261 residues, UniProt reviewed canonical sequence.

>P00414|MT-CO3
     1  MTHQSHAYHM VKPSPWPLTG ALSALLMTSG LAMWFHFHSM TLLMLGLLTN TLTMYQWWRD
    61  VTRESTYQGH HTPPVQKGLR YGMILFITSE VFFFAGFFWA FYHSSLAPTP QLGGHWPPTG
   121  ITPLNPLEVP LLNTSVLLAS GVSITWAHHS LMENNRNQMI QALLITILLG LYFTLLQASE
   181  YFESPFTISD GIYGSTFFVA TGFHGLHVII GSTFLTICFI RQLMFHFTSK HHFGFEAAAW
   241  YWHFVDVVWL FLYVSIYWWG S

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against MT-CO3 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
Other membrane
Secreted
No
Transmembrane segments
7
Mean surface accessibility (rSASA)
0.3
Highest tissue expression
238,539 nTPM

Expression across tissuesHPA

Tissue

  • heart muscle: 238,539 nTPM
  • kidney: 136,147 nTPM
  • choroid plexus: 132,189 nTPM
  • tongue: 129,464 nTPM
  • hippocampal formation: 122,683 nTPM
  • amygdala: 120,721 nTPM

Single-cell type

  • hepatocytes: 48,547 nCPM
  • colonocytes: 44,371 nCPM
  • enterocytes: 42,682 nCPM
  • enteric transient amplifying cells: 31,399 nCPM
  • retinal bipolar cells: 31,214 nCPM
  • goblet cells: 28,683 nCPM

Immune cell

  • classical monocyte: 4,720 nTPM
  • neutrophil: 3,647 nTPM
  • naive B-cell: 3,263 nTPM
  • memory B-cell: 2,943 nTPM
  • basophil: 2,884 nTPM
  • naive CD8 T-cell: 2,768 nTPM

Brain region

  • choroid plexus: 92,614 nTPM
  • medulla oblongata: 63,839 nTPM
  • thalamus: 60,575 nTPM
  • amygdala: 59,175 nTPM
  • pons: 56,989 nTPM
  • cerebral cortex: 56,103 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about MT-CO3.

Disease | AllUniProt

Conditions MT-CO3 is implicated in, by any mechanism.

  • Leber hereditary optic neuropathy (LHON) MIM:535000
  • Mitochondrial complex IV deficiency (MT-C4D) MIM:220110
  • Recurrent myoglobinuria mitochondrial (RM-MT) MIM:550500

Disease | GeneticClinVar

8 pathogenic / likely-pathogenic of 170 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

  • Cytochrome c oxidase subunit III-like
  • Cytochrome c oxidase, subunit III, 4-helical bundle
  • Cytochrome c oxidase subunit III
  • Cytochrome c oxidase subunit III domain
  • Cytochrome c oxidase subunit III-like superfamily
  • Cytochrome c oxidase subunit III

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads MT-CO3 as an antibody target. Whether an autoantibody or antibody against MT-CO3 could matter depends on whether native MT-CO3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

MT-CO3 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 MT-CO3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/MT-CO3. 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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