Affinage

COX10

Protoheme IX farnesyltransferase, mitochondrial · UniProt Q12887

Length
443 aa
Mass
48.9 kDa
Annotated
2026-04-28
30 papers in source corpus 14 papers cited in narrative 14 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

COX10 is a mitochondrial inner-membrane heme A:farnesyltransferase that catalyzes the farnesylation of protoheme (heme B) to heme O, the first committed step in heme A biosynthesis required for cytochrome c oxidase (Complex IV) assembly and oxidative phosphorylation (PMID:8118433, PMID:8078902). Heme A produced through COX10 (and subsequently COX15) is incorporated into the COX1 subunit prior to its association with COX4 and COX5A; in the absence of COX10, neither the COX1-containing subassembly nor the holoenzyme accumulates, resulting in severe isolated Complex IV deficiency (PMID:14607829, PMID:12928484). COX10 functions as a homo-oligomeric complex stabilized by the assembly factor Coa2, and its activity is post-translationally regulated by O-GlcNAcylation and transcriptionally suppressed under hypoxia via miR-210 (PMID:19841065, PMID:38778315, PMID:20498629). Loss-of-function mutations in COX10 cause autosomal recessive COX deficiency presenting as Leigh-like syndrome and progressive mitochondrial myopathy, confirmed by complementation rescue in patient fibroblasts and yeast (PMID:10767350, PMID:15455402, PMID:16103131).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 1990 High

    Identification of COX10 as a nuclear gene required post-translationally for cytochrome oxidase assembly established that COX biogenesis depends on dedicated nuclear-encoded factors beyond the structural subunits themselves.

    Evidence Genetic complementation of respiratory-deficient yeast mutants, nucleotide sequencing, and topological prediction of nine transmembrane segments

    PMID:2167310

    Open questions at the time
    • Enzymatic function not yet determined
    • Subcellular localization to mitochondrial inner membrane not directly demonstrated
    • Mammalian ortholog not yet identified
  2. 1993 High

    Biochemical analysis of heme constituents in cox10 mutant yeast demonstrated that COX10 catalyzes the farnesylation of protoheme to heme O, resolving its enzymatic identity as a heme A:farnesyltransferase.

    Evidence Chromatographic heme analysis in yeast cox10Δ mutants showing absence of heme O and heme A

    PMID:8118433

    Open questions at the time
    • In vitro reconstitution of farnesyltransferase activity not performed
    • Substrate specificity (farnesyl-PP vs. other isoprenoids) not directly tested
  3. 1994 High

    Functional complementation of yeast cox10Δ by human COX10 cDNA confirmed cross-species conservation of enzymatic function and enabled study of the human enzyme.

    Evidence Isolation of human cDNA from expression library by yeast complementation, Southern blot confirmation

    PMID:8078902

    Open questions at the time
    • Human enzyme kinetics not characterized
    • Tissue expression pattern not mapped
  4. 2000 High

    Discovery of a pathogenic homozygous COX10 missense mutation in a patient with COX deficiency established COX10 as a Mendelian disease gene and linked heme A biosynthesis to human mitochondrial disease.

    Evidence Genome-wide linkage analysis, mutation identification, and yeast complementation assay

    PMID:10767350

    Open questions at the time
    • Genotype-phenotype spectrum not yet defined
    • Residual enzymatic activity of mutant protein not quantified
  5. 2003 High

    Quantitative measurements in patient tissues and rescue experiments placed COX10 enzymatic activity upstream of COX1-COX4-COX5A subcomplex formation, defining its position in the assembly pathway and showing that heme A content directly determines COX holoenzyme abundance.

    Evidence Blue native PAGE of assembly intermediates across COX10-, SCO1-, and SURF1-deficient fibroblasts; retroviral complementation; heme A spectroscopic quantification

    PMID:12928484 PMID:14607829

    Open questions at the time
    • Direct physical interaction between COX10 and COX1 during heme insertion not demonstrated
    • Mechanism of heme A transfer to COX1 unknown
  6. 2004 High

    Identification of a start-codon mutation causing Leigh-like disease expanded the clinical spectrum and confirmed by overexpression rescue that even partial loss of COX10 protein is sufficient to cause severe COX deficiency.

    Evidence 2D gel electrophoresis and COX10 overexpression rescue in patient fibroblasts

    PMID:15455402

    Open questions at the time
    • Threshold of residual COX10 activity compatible with health not defined
  7. 2005 High

    A skeletal-muscle-specific Cox10 knockout mouse demonstrated in vivo that COX10-dependent heme A synthesis is essential for muscle COX activity and normal contractile function, providing an animal model of mitochondrial myopathy.

    Evidence Cre-lox conditional knockout (MLC1f-Cre), COX activity assays, force measurements

    PMID:16103131

    Open questions at the time
    • Whether compensatory metabolic remodeling occurs over time not fully characterized
    • Cardiac-specific consequences not addressed in this model
  8. 2010 High

    Genetic suppressor analysis in yeast revealed that COX10 functions as a homo-oligomeric complex stabilized by the Coa2 assembly factor, and that complex integrity is essential for its catalytic activity in heme A biosynthesis.

    Evidence Gain-of-function N196K suppressor of coa2Δ, epistasis with cox15Δ, oligomeric complex size analysis

    PMID:19841065

    Open questions at the time
    • Oligomeric stoichiometry not determined
    • Whether Coa2-like stabilization occurs in mammalian cells unknown
  9. 2010 Medium

    Identification of COX10 mRNA as a direct target of hypoxia-induced miR-210 revealed a transcriptional regulatory axis linking oxygen sensing to mitochondrial electron transport chain remodeling.

    Evidence miRNA target identification in cancer cell lines under hypoxia, mitochondrial function and ROS assays

    PMID:20498629

    Open questions at the time
    • Direct 3'UTR reporter validation not extensively detailed
    • Relative contribution of COX10 versus ISCU suppression to the metabolic phenotype not separated
  10. 2021 High

    NK cell-specific Cox10 deletion demonstrated that Complex IV-dependent oxidative phosphorylation is dispensable for homeostatic NK cell proliferation but specifically required for antigen-driven clonal expansion and memory formation, assigning COX10 a cell-type-specific immunological role.

    Evidence Ncr1-Cre conditional KO mice, MCMV infection, flow cytometry, metabolic flux analysis

    PMID:34077722

    Open questions at the time
    • Whether the metabolic requirement extends to other lymphocyte populations not tested
    • Mechanism by which glycolytic compensation fails to support clonal expansion unknown
  11. 2024 Medium

    Discovery that O-GlcNAcylation of COX10 protein by OGT enhances mitochondrial function during ischemia-reperfusion established post-translational modification as a regulatory mechanism for COX10 activity in the heart.

    Evidence Langendorff heart model, immunoprecipitation for O-GlcNAc, OGT/OGA pharmacological modulation

    PMID:38778315

    Open questions at the time
    • Specific O-GlcNAcylation site(s) on COX10 not mapped
    • Whether O-GlcNAcylation affects COX10 catalytic activity directly or its stability/oligomerization not distinguished
  12. 2024 High

    Systematic functional phenotyping of 25 human COX10 missense variants in yeast provided a quantitative genotype-activity map, directly correlating variant-specific COX10 residues with enzymatic output.

    Evidence Heterologous expression in yeast, COX activity measurement, non-fermentable carbon growth assays

    PMID:39152498

    Open questions at the time
    • Activity measurements performed in yeast, not in human cells
    • Structure-function mapping limited by absence of an atomic-resolution COX10 structure

Open questions

Synthesis pass · forward-looking unresolved questions
  • No atomic-resolution structure of COX10 exists, the mechanism of heme O transfer from COX10 to COX1 remains undefined, and the mammalian equivalent of the Coa2-dependent oligomeric regulation has not been established.
  • No structural model at atomic resolution
  • Heme O handoff mechanism to COX1 unknown
  • Mammalian COX10 oligomeric state and its regulators uncharacterized

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016740 transferase activity 5
Localization
GO:0005739 mitochondrion 4
Pathway
R-HSA-1430728 Metabolism 3 R-HSA-1852241 Organelle biogenesis and maintenance 3
Partners
COA2COX15MT-CO1OGT
Complex memberships
COX10 homo-oligomeric complex

Evidence

Reading pass · 14 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1990 COX10 encodes a nuclear gene product required for cytochrome oxidase assembly in yeast (S. cerevisiae); its product acts at a post-translational stage of enzyme assembly. The protein has a hydrophilic N-terminal domain and a hydrophobic C-terminal region with nine predicted transmembrane segments, and shares homology with ORF1 of the Paracoccus denitrificans cytochrome oxidase operon. Genetic complementation, nucleotide sequencing, hydrophobicity analysis, cytochrome oxidase subunit analysis in mutant yeast The Journal of biological chemistry High 2167310
1993 The yeast COX10 protein is required for heme A synthesis; specifically, it catalyzes the conversion of protoheme to heme O (farnesylation step), establishing its role as a farnesyl transferase in the heme A biosynthetic pathway. Heme constituent analysis in cox10 mutant yeast, biochemical chromatographic characterization Biochemistry and molecular biology international High 8118433
1994 Human COX10 encodes heme A:farnesyltransferase; the human cDNA was isolated by functional complementation of a yeast cox10 null mutant, confirming orthologous enzymatic function. Functional complementation of yeast cox10 null mutant with human cDNA library, Southern blot, PCR amplification Proceedings of the National Academy of Sciences of the United States of America High 8078902
2000 A homozygous missense mutation in human COX10 causes cytochrome c oxidase deficiency; complementation in yeast confirmed that COX10 encodes heme A:farnesyltransferase catalyzing the first step in protoheme-to-heme A conversion, and loss of COX10 function disrupts COX assembly. Genome-wide linkage mapping, mutation analysis, yeast complementation assay Human molecular genetics High 10767350
2003 COX10 catalyzes the conversion of protoheme (heme B) to heme O via farnesylation at C2; loss-of-function COX10 mutations reduce heme A content in patient muscle and fibroblasts proportional to reduction in COX enzyme activity and fully assembled enzyme. Retroviral expression of COX10 complements COX deficiency in patient fibroblasts. Missense mutations map to evolutionarily conserved residues in regions shown to have catalytic importance in prokaryotic orthologs. Retroviral complementation, heme A content measurement in patient mitochondria, microcell-mediated chromosome transfer, mutation analysis with topological modeling Human molecular genetics High 12928484
2003 In COX10-deficient patient fibroblasts, the COX subassembly containing MTCO1, COX4, and COX5A is absent (while it accumulates in SCO1- and SURF1-deficient cells), indicating that heme A incorporation into MTCO1 by COX10 occurs prior to association of MTCO1 with COX4 and COX5A during COX assembly. Blue native PAGE immunoblotting of native gel COX subassemblies in patient fibroblasts The Journal of biological chemistry High 14607829
2004 A homozygous mutation in the COX10 start codon causes COX deficiency with Leigh-like disease; overexpression of COX10 protein in patient fibroblasts rescues the defect, and 2D gel electrophoresis showed decreased fully assembled COX without accumulation of partial subcomplexes. 2D gel electrophoresis, western blot, overexpression rescue in patient fibroblasts Annals of neurology High 15455402
2005 Conditional knockout of COX10 in skeletal muscle (using Cre-lox under myosin light chain 1f promoter) causes isolated COX deficiency (<5% of control COX activity) and progressive mitochondrial myopathy, demonstrating that COX10-dependent heme A synthesis is required for COX activity and normal muscle function in vivo. Conditional knockout mouse model (Cre-lox), COX activity assay, muscle force/fatigue measurement, oxidative damage and apoptosis assays Human molecular genetics High 16103131
2010 In yeast, the Coa2 assembly factor stabilizes the oligomeric Cox10 farnesyl transferase complex involved in heme a addition to Cox1. A gain-of-function N196K substitution in Cox10 suppresses the respiratory deficiency of coa2Δ cells, and this suppressor activity depends on Cox10 catalytic function and the presence of Cox15 (the second heme A biosynthetic enzyme). The N196K substitution correlates with stabilization of the high-mass homo-oligomeric Cox10 complex. Genetic suppressor analysis, respiratory growth assays, yeast genetics (double mutants), complex size analysis Molecular and cellular biology High 19841065
2010 miR-210 directly targets COX10 mRNA (along with ISCU), reducing COX10 expression under hypoxia, thereby decreasing mitochondrial function and increasing glycolysis and reactive oxygen species generation in cancer cells. miRNA target identification in cancer cell lines, hypoxia experiments, mitochondrial function assays, ROS measurement Oncogene Medium 20498629
2013 COX10 mutations causing amino acid substitutions at conserved residues (Asp336Val and Arg339Trp) result in absence of detectable COX holoenzyme and subassemblies on blue-native gels, reduced MTCO1 on denaturing gels, and low heme aa3 content by absorption spectroscopy, consistent with heme A:farnesyltransferase deficiency. Both mutations were confirmed pathogenic by yeast respiratory deficiency assay. Blue native PAGE immunoblot, heme absorption spectroscopy, yeast functional assay, protein structural modeling JAMA neurology High 24100867
2021 NK cell-specific deletion of Cox10 (inducible Ncr1-Cox10Δ/Δ mice) impairs antigen-specific Ly49H+ NK cell expansion and memory formation during murine cytomegalovirus infection, while homeostatic proliferation is intact. Cox10-deficient NK cells upregulate glycolysis with increased AMPK and mTOR activation, demonstrating that oxidative phosphorylation (COX10-dependent complex IV activity) is specifically required for antigen-driven NK cell proliferation in vivo. Conditional KO mouse, viral infection model (MCMV), flow cytometry, metabolic flux assays, in vitro proliferation assays Cell reports High 34077722
2024 Mild therapeutic hypothermia upregulates O-GlcNAcylation of COX10 protein (mediated by OGT), which improves mitochondrial function and reduces ROS in myocardial ischemia-reperfusion injury. Pharmacological inhibition of OGT (ALX) reduces COX10 O-GlcNAcylation and abolishes the cardioprotective effect, while OGA inhibition enhances it. Langendorff isolated heart model, hypoxia/reoxygenation cell model, immunoprecipitation, western blot, OGT/OGA pharmacological modulation, immunofluorescence Journal of translational medicine Medium 38778315
2024 25 human COX10 missense variants were expressed in yeast and phenotyped; 11 variants supported ~half or more wild-type cytochrome c oxidase activity and growth on non-fermentable carbon sources, while the remainder showed severely reduced COX activity, directly correlating COX10 variant status with enzymatic function. Heterologous expression of human COX10 variants in yeast, COX activity assay, non-fermentable carbon source growth assay BMC research notes High 39152498

Source papers

Stage 0 corpus · 30 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 Hypoxia-regulated microRNA-210 modulates mitochondrial function and decreases ISCU and COX10 expression. Oncogene 335 20498629
2000 A mutation in the human heme A:farnesyltransferase gene (COX10 ) causes cytochrome c oxidase deficiency. Human molecular genetics 241 10767350
2003 Mutations in COX10 result in a defect in mitochondrial heme A biosynthesis and account for multiple, early-onset clinical phenotypes associated with isolated COX deficiency. Human molecular genetics 194 12928484
2005 Mice lacking COX10 in skeletal muscle recapitulate the phenotype of progressive mitochondrial myopathies associated with cytochrome c oxidase deficiency. Human molecular genetics 140 16103131
1990 COX10 codes for a protein homologous to the ORF1 product of Paracoccus denitrificans and is required for the synthesis of yeast cytochrome oxidase. The Journal of biological chemistry 122 2167310
2003 Cytochrome c oxidase subassemblies in fibroblast cultures from patients carrying mutations in COX10, SCO1, or SURF1. The Journal of biological chemistry 115 14607829
1993 On the functions of the yeast COX10 and COX11 gene products. Biochemistry and molecular biology international 94 8118433
1994 Isolation of a human cDNA for heme A:farnesyltransferase by functional complementation of a yeast cox10 mutant. Proceedings of the National Academy of Sciences of the United States of America 80 8078902
2019 Rhodiola crenulata attenuates apoptosis and mitochondrial energy metabolism disorder in rats with hypobaric hypoxia-induced brain injury by regulating the HIF-1α/microRNA 210/ISCU1/2(COX10) signaling pathway. Journal of ethnopharmacology 73 30878546
1997 The human COX10 gene is disrupted during homologous recombination between the 24 kb proximal and distal CMT1A-REPs. Human molecular genetics 72 9285799
2016 Screening and Characterization of a Non-cyp51A Mutation in an Aspergillus fumigatus cox10 Strain Conferring Azole Resistance. Antimicrobial agents and chemotherapy 62 27799210
2004 Cytochrome c oxidase biogenesis in a patient with a mutation in COX10 gene. Annals of neurology 43 15455402
2010 The role of Coa2 in hemylation of yeast Cox1 revealed by its genetic interaction with Cox10. Molecular and cellular biology 35 19841065
2013 COX10 mutations resulting in complex multisystem mitochondrial disease that remains stable into adulthood. JAMA neurology 31 24100867
1997 Genomic structure and expression of the human heme A:farnesyltransferase (COX10) gene. Genomics 22 9177788
2021 Reliance on Cox10 and oxidative metabolism for antigen-specific NK cell expansion. Cell reports 20 34077722
1997 The Charcot-Marie-Tooth binary repeat contains a gene transcribed from the opposite strand of a partially duplicated region of the COX10 gene. Genomics 15 9403059
2021 Regulating COX10-AS1 / miR-142-5p / PAICS axis inhibits the proliferation of non-small cell lung cancer. Bioengineered 11 34323174
2021 The COX10-AS1/miR-641/E2F6 Feedback Loop Is Involved in the Progression of Glioma. Frontiers in oncology 10 34381702
2024 Mild therapeutic hypothermia upregulates the O-GlcNAcylation level of COX10 to alleviate mitochondrial damage induced by myocardial ischemia-reperfusion injury. Journal of translational medicine 9 38778315
2019 RNA-sequencing reveals that STRN, ZNF484 and WNK1 add to the value of mitochondrial MT-COI and COX10 as markers of unstable coronary artery disease. PloS one 8 31821324
2022 Long non coding RNA COX10-DT promotes the progression of breast cancer via the COX10-DT/miR-206/BDNF axis. Biochemical and biophysical research communications 7 36463760
2023 COX10-AS1-mediated miR-361-5p regulated cell invasion and migration by targeting SPRY1 in oral squamous cell carcinoma. American journal of translational research 6 37056821
2022 Knockdown of NCK1-AS1 inhibits the development of atherosclerosis by targeting miR-1197/COX10 axis. Journal of biological engineering 5 34986861
2024 Long Non-coding RNA COX10-AS1 Promotes Glioma Progression by Competitively Binding miR-1-3p to Regulate ORC6 Expression. Neuroscience 4 38244670
2024 Complex mitochondrial disease caused by the mutation of COX10 in a toddler: a case-report study. Annals of medicine and surgery (2012) 4 38846886
2020 A Novel COX10 Deletion Polymorphism as a Susceptibility Factor for Sudden Cardiac Death Risk in Chinese Populations. DNA and cell biology 4 33180568
2022 Biallelic COX10 Mutations and PMP22 Deletion in a Family With Leigh Syndrome and Hereditary Neuropathy With Liability to Pressure Palsy. Neurology. Genetics 3 36176336
2024 Phenotypic assessment of Cox10 variants and their implications for Leigh Syndrome. BMC research notes 1 39152498
2009 [Expression of COX10 in human non-obstructive azoospermia testes]. Zhonghua nan ke xue = National journal of andrology 0 19694371