Seroatlas · Human Serome Atlas

CPOX

Oxygen-dependent coproporphyrinogen-III oxidase, mitochondrial

Also known as: CPO, CPX, HCP, HEM6_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P36551
Gene
CPOX
Ensembl
ENSG00000080819
Chromosome
3
Canonical length
454 aa
Protein class
Disease related genes, Enzymes, Human disease related genes, Metabolic proteins, Potential drug targets, Predicted membrane proteins
Subcellular location
Mitochondria
Quaternary structure
Homodimer

OverviewNCBI Gene

The protein encoded by this gene is the sixth enzyme of the heme biosynthetic pathway. The encoded enzyme is soluble and found in the intermembrane space of mitochondria. This enzyme catalyzes the stepwise oxidative decarboxylation of coproporphyrinogen III to protoporphyrinogen IX, a precursor of heme. Defects in this gene are a cause of hereditary coproporphyria (HCP).[provided by RefSeq, Oct 2009]

Canonical amino-acid sequenceUniProt

454 residues, UniProt reviewed canonical sequence.

>P36551|CPOX
     1  MALQLGRLSS GPCWLVARGG CGGPRAWSQC GGGGLRAWSQ RSAAGRVCRP PGPAGTEQSR
    61  GLGHGSTSRG GPWVGTGLAA ALAGLVGLAT AAFGHVQRAE MLPKTSGTRA TSLGRPEEEE
   121  DELAHRCSSF MAPPVTDLGE LRRRPGDMKT KMELLILETQ AQVCQALAQV DGGANFSVDR
   181  WERKEGGGGI SCVLQDGCVF EKAGVSISVV HGNLSEEAAK QMRSRGKVLK TKDGKLPFCA
   241  MGVSSVIHPK NPHAPTIHFN YRYFEVEEAD GNKQWWFGGG CDLTPTYLNQ EDAVHFHRTL
   301  KEACDQHGPD LYPKFKKWCD DYFFIAHRGE RRGIGGIFFD DLDSPSKEEV FRFVQSCARA
   361  VVPSYIPLVK KHCDDSFTPQ EKLWQQLRRG RYVEFNLLYD RGTKFGLFTP GSRIESILMS
   421  LPLTARWEYM HSPSENSKEA EILEVLRHPR DWVR

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CPOX 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
0
Mean surface accessibility (rSASA)
0.36
Highest tissue expression
42 nTPM

Expression across tissuesHPA

Tissue

  • bone marrow: 42 nTPM
  • spinal cord: 35 nTPM
  • liver: 33 nTPM
  • duodenum: 20 nTPM
  • midbrain: 20 nTPM
  • placenta: 17 nTPM

Single-cell type

  • erythrocyte progenitors: 53 nCPM
  • oligodendrocytes: 28 nCPM
  • podocytes: 9.5 nCPM
  • megakaryocyte-erythroid progenitors: 9.3 nCPM
  • platelets: 8.5 nCPM
  • distal convoluted tubule cells: 8 nCPM

Immune cell

  • memory CD8 T-cell: 0.8 nTPM
  • naive CD8 T-cell: 0.8 nTPM
  • MAIT T-cell: 0.7 nTPM
  • classical monocyte: 0.6 nTPM
  • memory CD4 T-cell: 0.6 nTPM
  • NK-cell: 0.6 nTPM

Brain region

  • white matter: 63 nTPM
  • medulla oblongata: 44 nTPM
  • basal ganglia: 36 nTPM
  • pons: 33 nTPM
  • thalamus: 31 nTPM
  • midbrain: 30 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CPOX.

Disease | AllUniProt

Conditions CPOX is implicated in, by any mechanism.

Disease | GeneticClinVar

42 pathogenic / likely-pathogenic of 346 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

  • Coproporphyria
  • Hereditary coproporphyria
  • Harderoporphyria
  • CPOX-related hereditary coproporphyria
  • CPOX-related disorder

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)
0.54
gnomAD pLI
0.17
gnomAD missense Z
1.35
DepMap mean gene effect
-0.26
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 7% 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

  • Coproporphyrinogen III oxidase, aerobic
  • Coproporphyrinogen III oxidase, conserved site
  • Oxygen-dependent coproporphyrinogen III oxidase superfamily
  • Coproporphyrinogen III oxidase

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

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

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

Canonical record: https://seroatlas.com/gene/CPOX. 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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