Affinage

NDUFS8

NADH dehydrogenase [ubiquinone] iron-sulfur protein 8, mitochondrial · UniProt O00217

Length
210 aa
Mass
23.7 kDa
Annotated
2026-04-29
19 papers in source corpus 11 papers cited in narrative 10 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

NDUFS8 (TYKY) is a core nuclear-encoded subunit of mitochondrial respiratory Complex I that coordinates two [4Fe-4S] iron-sulfur clusters (N2a and N2b) through two conserved cysteine motifs and is essential for Complex I assembly, electron transfer, and cellular ATP production (PMID:9428698, PMID:12615348, PMID:34204592). Each conserved cysteine cluster ligates one [4Fe-4S] center; cysteine-to-serine mutations abolish the corresponding EPR signals and eliminate Complex I activity, while disease-associated mutations at subunit interfaces disrupt assembly of both the peripheral and membrane arms (PMID:12615348, PMID:36462614, PMID:15159508). NDUFS8 transcription is driven by YY1/Sp1 and NRF2, and its protein stability is regulated by HUWE1-mediated ubiquitination at Lys88 (PMID:11955626, PMID:41355955, PMID:40914145). Loss of NDUFS8 impairs oxidative phosphorylation, reduces ATP-dependent Akt-mTOR signaling in endothelial cells to compromise angiogenesis, and causes spatial memory deficits in chronic cerebral hypoperfusion models that are rescued by NDUFS8 restoration (PMID:38594244, PMID:41355955).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 1997 High

    Establishing that NDUFS8/TYKY is an iron-sulfur cluster subunit essential for Complex I assembly answered the fundamental question of what role this nuclear-encoded subunit plays in the enzyme: deletion or cysteine mutation in the bacterial ortholog abolished Complex I activity, eliminated FeS EPR signals, and destabilized both the peripheral and membrane arms.

    Evidence Homologous recombination deletion and Cys-to-Ser mutagenesis in R. capsulatus NuoI with EPR spectroscopy and immunochemical analysis; parallel biochemical fractionation of N. crassa Complex I

    PMID:9116042 PMID:9428698 PMID:9452770

    Open questions at the time
    • Exact identity of which cysteine cluster coordinates which FeS center was not resolved
    • Human NDUFS8 function was inferred from orthologs, not directly demonstrated
  2. 2002 Medium

    Identifying YY1 and Sp1 as transcriptional regulators of NDUFS8 answered how expression of this essential Complex I subunit is controlled, revealing a compact 247 bp promoter whose activity depends on defined factor-binding sites.

    Evidence Primer extension, EMSA, reporter assays, and site-directed mutagenesis of YY1/Sp1 sites in the NDUFS8 promoter

    PMID:11955626

    Open questions at the time
    • Whether YY1/Sp1 regulation is rate-limiting for Complex I biogenesis in vivo was not tested
    • Coordination with other mitochondrial biogenesis programs (PGC-1α/NRF1) was not examined
  3. 2003 High

    Mapping each conserved cysteine motif to a specific [4Fe-4S] cluster (N2a or N2b) resolved the ambiguity about iron-sulfur cluster assignment within NDUFS8, showing that each motif independently coordinates one cluster.

    Evidence Individual Cys-to-Ser substitutions in R. capsulatus NuoI with quantitative EPR spectroscopy and Complex I activity assays

    PMID:12615348

    Open questions at the time
    • Structural resolution of cluster–protein contacts awaited crystallography
    • Functional distinction between N2a and N2b in electron transfer was not established
  4. 2004 Medium

    Demonstrating that patient NDUFS8 mutations destabilize multiple Complex I subunits established the subunit as a structural linchpin whose loss cascades across the holoenzyme.

    Evidence Western blot of Complex I subunits in fibroblasts from patients with compound heterozygous NDUFS8 mutations

    PMID:15159508

    Open questions at the time
    • Assembly intermediates were not characterized
    • Whether residual Complex I activity correlates with clinical severity was not quantified
  5. 2021 Medium

    Functional rescue of Complex I assembly and activity by TAT-fused NDUFS8 protein transduction proved that the mature subunit alone is sufficient to restore enzyme function in deficient cells, validating NDUFS8 as the rate-limiting component.

    Evidence TAT-NDUFS8 fusion protein delivery to NDUFS8-deficient human cells with in-gel activity, oxygen consumption, and assembly assays

    PMID:34204592

    Open questions at the time
    • Rescue was partial; whether full activity requires co-import with assembly factors is unknown
    • Long-term stability and turnover of exogenously delivered NDUFS8 were not assessed
  6. 2022 Medium

    Modeling disease-associated NDUFS8 mutations at subunit interfaces in E. coli showed that pathogenicity arises from disrupted inter-subunit contacts rather than intra-subunit folding, explaining the assembly defect mechanism.

    Evidence Site-directed mutagenesis of E. coli nuoI at positions corresponding to patient mutations, activity assays, co-immunoprecipitation, and time-delayed assembly assays

    PMID:36462614

    Open questions at the time
    • Bacterial model may not recapitulate mammalian-specific assembly intermediates
    • Structural validation by cryo-EM or cross-linking mass spectrometry was not performed
  7. 2024 Medium

    Establishing that NDUFS8 sustains angiogenesis through an ATP→Akt-mTOR signaling axis extended its role beyond bioenergetics to a specific developmental signaling output, with epistasis experiments defining the causal order.

    Evidence shRNA/CRISPR KO in HUVECs, ATP rescue and constitutively-active Akt1 epistasis, in vivo AAV-shRNA in retinal model

    PMID:38594244

    Open questions at the time
    • Whether the Akt-mTOR axis is the sole effector of NDUFS8-dependent ATP signaling is unclear
    • Contribution of ROS versus ATP deficit to the phenotype was not fully disentangled
  8. 2025 Medium

    Identifying HUWE1 as the E3 ligase that ubiquitinates NDUFS8 at Lys88 answered how NDUFS8 protein turnover is controlled post-translationally, linking proteostasis to Complex I activity regulation.

    Evidence Mass spectrometry, co-IP, ubiquitination assays, and functional studies in HCC cells and xenograft models

    PMID:40914145

    Open questions at the time
    • Whether Lys88 ubiquitination targets NDUFS8 for proteasomal versus mitophagic degradation is unresolved
    • Ubiquitination dynamics under metabolic stress were not examined
  9. 2026 Medium

    Demonstrating that NRF2 transcriptionally and post-transcriptionally regulates NDUFS8 and that NDUFS8 restoration rescues cognitive deficits in chronic cerebral hypoperfusion linked oxidative stress responses to Complex I biogenesis and neuroprotection.

    Evidence ChIP, dual-luciferase reporter assays, AAV-mediated NDUFS8 overexpression/knockdown in rat basal forebrain, behavioral and metabolic rescue

    PMID:41355955

    Open questions at the time
    • Mechanism by which cytoplasmic NRF2 stabilizes NDUFS8 protein is undefined
    • Whether NRF2-NDUFS8 axis operates in human neurodegeneration is not established

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include the structural basis for how NDUFS8 bridges the peripheral and membrane arms of mammalian Complex I, whether N2a and N2b clusters have distinct roles in electron transfer, and how HUWE1-mediated ubiquitination is coordinated with mitochondrial import and assembly kinetics.
  • No high-resolution structural data specifically addressing NDUFS8 cluster–subunit interface contacts in mammalian Complex I
  • Functional distinction between N2a and N2b clusters in electron relay remains untested
  • Integration of transcriptional (YY1/Sp1/NRF2) and post-translational (HUWE1) regulation in physiological contexts is unexplored

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Localization
GO:0005739 mitochondrion 6
Pathway
R-HSA-1430728 Metabolism 5 R-HSA-162582 Signal Transduction 1
Partners
HUWE1NRF2SP1YY1
Complex memberships
Complex I (NADH:ubiquinone oxidoreductase)

Evidence

Reading pass · 10 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1997 NDUFS8 (TYKY subunit) contains two clusters of four conserved cysteine residues, and its bacterial ortholog NuoI (R. capsulatus) is required for proper assembly of both the membraneous and peripheral domains of Complex I; deletion or Cys74Ser point mutation abolishes Complex I activity and eliminates EPR signals for FeS clusters N1 and N2, while a limited amount of C74S NuoI still binds the membraneous domain, indicating direct interaction with that domain. Homologous recombination deletion and point mutagenesis in R. capsulatus, EPR spectroscopy, immunochemical analysis of mutant membranes, trans-complementation European journal of biochemistry High 9428698
1997 The mature NDUFS8/TYKY protein is processed from a precursor by cleavage of a 34-amino-acid N-terminal mitochondrial targeting presequence, yielding a mature protein of ~21-22 kDa that is closely associated with the peripheral arm of Complex I. cDNA sequencing, heterologous expression in E. coli, purification, antiserum production, subcellular fractionation of N. crassa Complex I Biochimica et biophysica acta Medium 9116042 9452770
2003 The NuoI/TYKY subunit (ortholog of NDUFS8) binds two [4Fe-4S] clusters designated N2a and N2b; cysteine-to-serine substitutions in the two conserved cysteine motifs each cause a specific ~50% decrease of the EPR N2 cluster signal, demonstrating that each cysteine cluster coordinates one [4Fe-4S] cluster. Site-directed mutagenesis of five conserved cysteines in R. capsulatus NuoI, EPR spectroscopy of membrane vesicles, Complex I activity assays Biochimica et biophysica acta High 12615348
2004 Loss-of-function mutations in NDUFS8 reduce not only the NDUFS8 polypeptide but also other nuclear-encoded subunits of Complex I, indicating that NDUFS8 is essential for the assembly or stability of Complex I. Western blot analysis of patient fibroblasts carrying compound heterozygous NDUFS8 mutations Neurology Medium 15159508
2002 Transcription of the NDUFS8 gene is driven by YY1 and Sp1 transcription factors binding to a 247 bp minimal promoter; site-directed mutagenesis of the YY1 site and two adjacent Sp1 sites abolishes most promoter activity, as confirmed by gel shift assays. Primer extension, reporter gene assays, gel shift (EMSA), site-directed mutagenesis Biochimica et biophysica acta Medium 11955626
2021 TAT peptide-fused NDUFS8 (TAT-NDUFS8) is imported into mitochondria in a membrane-potential-independent manner, is correctly processed, restores Complex I assembly in NDUFS8-deficient cells, and partially rescues Complex I enzymatic activity. TAT-fusion protein transduction into human cells, mitochondrial fractionation, in-gel Complex I activity assay, oxygen consumption assay International journal of molecular sciences Medium 34204592
2022 Disease-associated mutations in NDUFS8 (modeled in homologous E. coli nuoI) map to subunit interfaces and disrupt Complex I assembly, as shown by reduced deamino-NADH oxidase activity, assembly assays, time-delayed expression, and co-immunoprecipitation. Bacterial mutagenesis (E. coli nuoI), membrane vesicle activity assays, co-immunoprecipitation, assembly assays Mitochondrion Medium 36462614
2024 NDUFS8 loss-of-function in endothelial cells (shRNA/CRISPR KO) reduces Complex I activity, oxygen consumption, ATP production, and activates oxidative stress; NDUFS8 supports angiogenesis by sustaining Akt-mTOR signaling downstream of ATP production, as exogenous ATP and constitutively active Akt1 rescue the proliferation/migration/tube-formation defects. shRNA knockdown and CRISPR/Cas9 KO in HUVECs, mitochondrial function assays, Akt-mTOR pathway analysis, ATP rescue experiment, constitutively-active Akt1 re-activation, in vivo AAV-shRNA retinal model Cell death & disease Medium 38594244
2025 HUWE1 is the E3 ubiquitin ligase that ubiquitinates NDUFS8 at lysine 88, regulating its protein stability; NDUFS8 localizes to mitochondria and promotes Complex I activity and ATP production in hepatocellular carcinoma cells. Mass spectrometry, co-immunoprecipitation, ubiquitination assay, knockdown/knockout/overexpression in HCC cells, mitochondrial function assays, xenograft mouse model Translational oncology Medium 40914145
2026 NRF2 transcriptionally regulates NDUFS8 through both ARE and non-ARE motifs in the NDUFS8 promoter; cytoplasmic NRF2 also stabilizes NDUFS8 protein; restoration of NDUFS8 in basal forebrain rescues mitochondrial oxidative phosphorylation and spatial memory deficits in a chronic cerebral hypoperfusion rat model. Dual-luciferase reporter assays, chromatin immunoprecipitation (ChIP), AAV-mediated NDUFS8 overexpression/knockdown in rat basal forebrain, transcriptomic-proteomic analysis Theranostics Medium 41355955

Source papers

Stage 0 corpus · 19 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2004 Late-onset Leigh syndrome in a patient with mitochondrial complex I NDUFS8 mutations. Neurology 71 15159508
1997 cDNA sequence and chromosomal localization of the NDUFS8 human gene coding for the 23 kDa subunit of the mitochondrial complex I. Biochimica et biophysica acta 34 9116042
1997 The NuoI subunit of the Rhodobacter capsulatus respiratory Complex I (equivalent to the bovine TYKY subunit) is required for proper assembly of the membraneous and peripheral domains of the enzyme. European journal of biochemistry 31 9428698
2003 Two EPR-detectable [4Fe-4S] clusters, N2a and N2b, are bound to the NuoI (TYKY) subunit of NADH:ubiquinone oxidoreductase (Complex I) from Rhodobacter capsulatus. Biochimica et biophysica acta 20 12615348
1998 Genomic structure of the human NDUFS8 gene coding for the iron-sulfur TYKY subunit of the mitochondrial NADH:ubiquinone oxidoreductase. Gene 20 9666055
2024 The requirement of the mitochondrial protein NDUFS8 for angiogenesis. Cell death & disease 17 38594244
2012 NDUFS8-related Complex I Deficiency Extends Phenotype from "PEO Plus" to Leigh Syndrome. JIMD reports 15 23430795
2002 YY1 and Sp1 activate transcription of the human NDUFS8 gene encoding the mitochondrial complex I TYKY subunit. Biochimica et biophysica acta 13 11955626
2022 Role of the Gene ndufs8 Located in Respiratory Complex I from Monascus purpureus in the Cell Growth and Secondary Metabolites Biosynthesis. Journal of fungi (Basel, Switzerland) 9 35887413
1997 Identification of the TYKY homologous subunit of complex I from Neurospora crassa. Biochimica et biophysica acta 9 9452770
2021 TAT-Conjugated NDUFS8 Can Be Transduced into Mitochondria in a Membrane-Potential-Independent Manner and Rescue Complex I Deficiency. International journal of molecular sciences 8 34204592
2022 Higher NADH Dehydrogenase [Ubiquinone] Iron-Sulfur Protein 8 (NDUFS8) Serum Levels Correlate with Better Insulin Sensitivity in Type 1 Diabetes. Current issues in molecular biology 4 36135178
2024 Human umbilical mesenchymal stem cells ameliorate atrophic gastritis in aging mice by participating in mitochondrial autophagy through Ndufs8 signaling. Stem cell research & therapy 3 39707499
2024 Mitochondrial complex I subunit NDUFS8.2 modulates responses to stresses associated with reduced water availability. Plant physiology and biochemistry : PPB 2 38428158
2022 Expansion of the clinical and neuroimaging spectrum associated with NDUFS8-related disorder. JIMD reports 2 36101822
2022 Analysis of compound heterozygous and homozygous mutations found in peripheral subunits of human respiratory Complex I, NDUFS1, NDUFS2, NDUFS8 and NDUFV1, by modeling in the E. coli enzyme. Mitochondrion 2 36462614
2025 NDUFS8-Related Leigh Syndrome Mimicking a Leukodystrophy. Journal of child neurology 1 40239028
2026 Targeting NDUFS8 in basal forebrain ameliorates cognitive decline related to chronic cerebral hypoperfusion. Theranostics 0 41355955
2025 NDUFS8 facilitates hepatocellular carcinoma growth by enhancing mitochondrial function and escaping HUWE1-dependent degradation. Translational oncology 0 40914145