Affinage

NDUFS8

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

Length
210 aa
Mass
23.7 kDa
Annotated
2026-06-10
19 papers in source corpus 12 papers cited in narrative 12 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

NDUFS8 (TYKY) is a nuclear-encoded core iron-sulfur subunit of mitochondrial Complex I that is essential for assembly of the holoenzyme and for NADH:ubiquinone oxidoreductase activity (PMID:9116042, PMID:15159508). It carries two distinct [4Fe-4S] clusters, N2a and N2b, each coordinated by a separate set of conserved cysteine residues, and mutation of these cysteines diminishes the N2 EPR signal and abolishes electron transfer activity (PMID:12615348). The subunit physically connects the peripheral and membrane domains of Complex I; loss of the ortholog or disease-associated mutations at subunit interfaces prevent assembly and cause secondary loss of other nuclear-encoded subunits (PMID:9428698, PMID:15159508, PMID:36462614). Functionally, NDUFS8-dependent Complex I activity sustains ATP production and mitochondrial integrity, and its loss depolarizes mitochondria and elevates ROS; in endothelial cells this ATP supply drives Akt-mTOR signaling to support proliferation, migration, and angiogenesis (PMID:38594244), and restoration of NDUFS8 in the basal forebrain rescues memory deficits by enhancing oxidative phosphorylation (PMID:41355955). Transcription is controlled by a minimal promoter in which a YY1 site and adjacent Sp1 sites are the primary drivers (PMID:11955626), with NRF2 additionally activating the gene through ARE and non-ARE motifs and stabilizing the protein post-translationally (PMID:41355955), while the E3 ligase HUWE1 ubiquitinates NDUFS8 at lysine 88 to regulate its stability (PMID:40914145). Compound heterozygous mutations in NDUFS8 cause Leigh syndrome through Complex I deficiency (PMID:15159508).

Mechanistic history

Synthesis pass · year-by-year structured walk · 11 steps
  1. 1997 Medium

    Establishing NDUFS8's molecular identity was the first step: cloning showed it encodes a mitochondrially-targeted iron-sulfur subunit with two conserved cysteine clusters, predicting a metal-cofactor role in Complex I.

    Evidence cDNA sequencing, deduced protein and cross-species conservation analysis

    PMID:9116042

    Open questions at the time
    • Did not demonstrate which clusters the cysteines coordinate
    • No direct functional or assembly data
  2. 1997 High

    Whether the subunit is functionally required was answered by ortholog deletion and cysteine mutagenesis, showing it is essential for Complex I activity, FeS cluster signals, and assembly bridging the peripheral and membrane arms.

    Evidence Homologous recombination deletion, C74S mutagenesis, EPR, and trans-complementation in Rhodobacter capsulatus

    PMID:9428698

    Open questions at the time
    • Performed in a bacterial ortholog rather than human protein
    • Did not resolve the number of FeS clusters carried
  3. 1998 Medium

    Gene/protein structural characterization defined the mature ~22 kDa product and identified Sp1 and NRF1 motifs, opening the question of how transcription is controlled.

    Evidence Genomic sequencing, 2D gel electrophoresis, immunodetection

    PMID:9666055

    Open questions at the time
    • Promoter motifs not functionally validated
    • Tissue-specificity correlative only
  4. 2002 High

    The basal transcriptional control was resolved, identifying a minimal promoter where a YY1 site and adjacent Sp1 sites drive expression.

    Evidence Reporter assays, EMSA, and site-directed mutagenesis in HeLa and C2C12 cells

    PMID:11955626

    Open questions at the time
    • Did not address inducible or stress-responsive regulation
    • No in vivo promoter validation
  5. 2003 High

    The cofactor content was settled by systematic cysteine mutagenesis with EPR, demonstrating the subunit carries two distinct [4Fe-4S] clusters, N2a and N2b.

    Evidence Site-directed mutagenesis of five cysteines, EPR spectroscopy, NADH:ubiquinone oxidoreductase assays in ortholog

    PMID:12615348

    Open questions at the time
    • Ortholog system; human cluster assignment inferred
    • Functional role of each cluster in electron transfer not separated
  6. 2004 Medium

    The human disease relevance was established: compound heterozygous mutations cause Leigh syndrome with reduced NDUFS8 and secondary loss of other subunits, confirming its role in holoenzyme assembly/stability.

    Evidence Mutation analysis and Western blot of patient tissue

    PMID:15159508

    Open questions at the time
    • Single patient
    • Assembly defect inferred from steady-state protein levels, not assembly intermediates
  7. 2021 Medium

    A delivery-based rescue addressed therapeutic restoration, showing exogenous TAT-NDUFS8 enters mitochondria potential-independently and partially restores Complex I assembly and activity in deficient cells.

    Evidence TAT-fusion protein transduction, mitochondrial fractionation, in-gel activity and oxygen consumption assays

    PMID:34204592

    Open questions at the time
    • Only partial activity restoration
    • Single cell model
  8. 2022 Medium

    Structure-function mapping of patient mutations clarified that specific variants act at subunit interfaces to block assembly, and ranked the more deleterious allele in compound heterozygotes.

    Evidence nuoI mutagenesis in E. coli, co-immunoprecipitation, assembly and deamino-NADH oxidase assays

    PMID:36462614

    Open questions at the time
    • E. coli surrogate model
    • Interface assignments not confirmed in human Complex I
  9. 2024 High

    The downstream physiological consequence was defined: NDUFS8-driven ATP production feeds Akt-mTOR signaling to control endothelial proliferation and angiogenesis in vitro and in vivo.

    Evidence shRNA/CRISPR KO and overexpression, OCR/ATP/ROS assays, constitutively-active Akt rescue, AAV in vivo retinal angiogenesis

    PMID:38594244

    Open questions at the time
    • Mechanistic link is ATP-dependent but molecular coupling to Akt unresolved
    • Restricted to endothelial context
  10. 2025 Medium

    Post-translational regulation was identified, with HUWE1 ubiquitinating NDUFS8 at K88 to control its stability and influence ATP/ROS balance and apoptosis in cancer cells.

    Evidence Mass spectrometry, co-IP, ubiquitination assay, functional KO/OE, xenograft

    PMID:40914145

    Open questions at the time
    • Single lab interactor
    • Consequence of K88 ubiquitination on degradation kinetics not fully mapped
  11. 2026 Medium

    Stress-responsive transcriptional and protein-level regulation was added, showing NRF2 both activates the promoter via ARE/non-ARE motifs and stabilizes the protein, with restoration rescuing cognitive deficits.

    Evidence Dual-luciferase, ChIP, AAV gain/loss-of-function in basal forebrain, behavioral and OXPHOS assays

    PMID:41355955

    Open questions at the time
    • Mechanism of cytoplasmic NRF2 protein stabilization unresolved
    • Non-ARE binding mode not structurally defined

Open questions

Synthesis pass · forward-looking unresolved questions
  • How NDUFS8's two FeS clusters mediate electron transfer within the human Complex I architecture, and how its transcriptional, ubiquitin, and NRF2-mediated regulatory layers are integrated under physiological stress, remain open.
  • No structural model of human NDUFS8 within assembled Complex I in the corpus
  • Interplay between HUWE1 ubiquitination and NRF2 stabilization not reconciled

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005198 structural molecule activity 2 GO:0016491 oxidoreductase activity 2 GO:0140098 catalytic activity, acting on RNA 2
Localization
GO:0005739 mitochondrion 3
Pathway
R-HSA-1430728 Metabolism 2 R-HSA-1643685 Disease 2
Partners
HUWE1NRF2SP1YY1
Complex memberships
Mitochondrial respiratory Complex I (NADH:ubiquinone oxidoreductase)

Evidence

Reading pass · 12 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 encodes a 210-amino-acid precursor with a 34-amino-acid N-terminal mitochondrial targeting presequence; the mature protein is 92% identical to the bovine subunit and 72% to the Rhodobacter capsulatus NuoI counterpart, establishing it as an iron-sulfur subunit of Complex I. cDNA sequencing, deduced protein analysis, chromosomal mapping Biochimica et biophysica acta Medium 9116042
1997 Deletion of the NuoI (TYKY ortholog) gene or mutation of a conserved cysteine (C74S) in Rhodobacter capsulatus abolishes Complex I activity, eliminates EPR signals for FeS clusters N1 and N2, and prevents assembly of peripheral subunits, demonstrating that NuoI is required for connecting the peripheral and membraneous domains of Complex I. Homologous recombination deletion, site-directed mutagenesis (C74S), EPR spectroscopy, immunochemical analysis, trans-complementation European journal of biochemistry High 9428698
1997 The TYKY/NDUFS8 homolog in Neurospora crassa is closely associated with the peripheral arm of Complex I, as shown by co-purification and antiserum-based localization. Heterologous expression in E. coli, purification, antibody production, biochemical fractionation Biochimica et biophysica acta Medium 9452770
1998 The mature NDUFS8/TYKY protein has a molecular mass of ~22 kDa and a pI of 4.9–5.0, as determined by 2D gel electrophoresis and immunodetection; the gene spans ~6 kb with seven exons, and its promoter contains Sp1 and NRF1 binding site motifs in the first intron, with ubiquitous expression predominant in heart and skeletal muscle. Genomic sequencing, 2D gel electrophoresis, immunodetection Gene Medium 9666055
2002 Transcription of NDUFS8 is driven by a minimal 247-bp basal promoter containing three Sp1 sites and one YY1 site; gel-shift analysis and site-directed mutagenesis showed that the YY1 site and two adjacent Sp1 sites are the primary drivers of promoter activity. Primer extension, reporter gene assay (HeLa and C2C12 cells), gel-shift (EMSA), site-directed mutagenesis Biochimica et biophysica acta High 11955626
2003 The NuoI (TYKY) subunit of Complex I binds two distinct [4Fe-4S] clusters, named N2a and N2b, each coordinated by a separate set of conserved cysteine residues; cysteine mutants C67S and C106S each caused a 50% decrease in the EPR N2 signal, demonstrating that both N2 clusters reside on this subunit. Site-directed mutagenesis of five cysteine residues, EPR spectroscopy of membrane fractions, NADH:ubiquinone oxidoreductase activity assays Biochimica et biophysica acta High 12615348
2004 Compound heterozygous mutations in NDUFS8 in a Leigh syndrome patient cause reduced levels of the NDUFS8 polypeptide and secondary reductions in other nuclear-encoded Complex I subunits, indicating NDUFS8 is essential for the assembly or stability of the Complex I holoenzyme. Mutation analysis, Western blot of patient-derived tissue Neurology Medium 15159508
2021 TAT-fused NDUFS8 fusion proteins are transduced into mitochondria in a membrane-potential-independent manner, are correctly processed, rescue Complex I assembly, and partially restore Complex I activity in NDUFS8-deficient cells. Recombinant TAT-fusion protein production, cell transduction, mitochondrial fractionation, in-gel activity assay, oxygen consumption assay International journal of molecular sciences Medium 34204592
2022 Disease-associated mutations in NDUFS8 (mapped to the nuoI locus in E. coli Complex I) disrupt Complex I assembly; co-immunoprecipitation and time-delayed expression assays confirmed that certain mutations act at subunit interfaces, and compound heterozygote modeling identified the more deleterious mutation in each pair. Site-directed mutagenesis in E. coli homolog (nuoI), deamino-NADH oxidase activity, co-immunoprecipitation, assembly assay Mitochondrion Medium 36462614
2024 NDUFS8 knockdown or knockout in endothelial cells reduces Complex I activity, decreases ATP production, depolarizes mitochondria, and increases ROS; these effects impair the Akt-mTOR signaling cascade, which is rescuable by exogenous ATP. Conversely, NDUFS8 overexpression promotes Akt-mTOR activation, cell proliferation, migration, and tube formation. Endothelial-specific NDUFS8 knockdown in vivo inhibits retinal angiogenesis. shRNA/CRISPR-Cas9 KO, oxygen consumption assay, ATP assay, ROS measurement, mitochondrial membrane potential assay, Akt-mTOR pathway analysis, constitutively-active Akt1 rescue, AAV-mediated in vivo knockdown, retinal angiogenesis assay Cell death & disease High 38594244
2025 HUWE1 is an E3 ubiquitin ligase that ubiquitinates NDUFS8 at lysine 88, regulating its protein stability; NDUFS8 localizes to mitochondria, promotes Complex I activity and ATP production in hepatocellular carcinoma cells, and its loss increases ROS, disrupts redox homeostasis, and induces apoptosis. Mass spectrometry, co-immunoprecipitation, ubiquitination assay, mitochondrial fractionation, shRNA/KO/OE functional assays, xenograft mouse model Translational oncology Medium 40914145
2026 NRF2 regulates NDUFS8 transcription by binding both ARE and non-ARE motifs in the NDUFS8 promoter; cytoplasmic NRF2 also stabilizes NDUFS8 protein post-translationally. AAV-mediated NDUFS8 restoration in basal forebrain rescues spatial memory deficits in chronic cerebral hypoperfusion rats by enhancing mitochondrial oxidative phosphorylation. Dual-luciferase reporter assay, chromatin immunoprecipitation (ChIP), computational simulation, stereotaxic AAV injection with gain/loss-of-function, behavioral memory assay, mitochondrial OXPHOS measurement 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 18 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
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 4 36462614
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
2022 Expansion of the clinical and neuroimaging spectrum associated with NDUFS8-related disorder. JIMD reports 3 36101822
2024 Mitochondrial complex I subunit NDUFS8.2 modulates responses to stresses associated with reduced water availability. Plant physiology and biochemistry : PPB 2 38428158
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

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