Affinage

NDUFA1

NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 1 · UniProt O15239

Length
70 aa
Mass
8.1 kDa
Annotated
2026-06-10
16 papers in source corpus 10 papers cited in narrative 10 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

NDUFA1 (MWFE) is an essential, small inner mitochondrial membrane subunit of respiratory complex I, required for assembly and activity of the holoenzyme: its loss abolishes detectable high-molecular-weight complex I and reduces complex I activity to <10% of normal, with restoration upon reintroduction of the cDNA (PMID:10200266, PMID:11937507). Its first ~30 residues form a minimal mitochondrial targeting sequence that doubles as a stop-transfer signal, fixing the protein's orientation in the inner membrane and within complex I, and this membrane anchor cannot be functionally substituted by that of another complex I subunit (PMID:16120368). NDUFA1 physically interacts with mtDNA-encoded integral membrane subunits, and is itself unstable in their absence; the region spanning residues 39–46 determines species-specific compatibility between the nuclear-encoded protein and the mitochondrial-encoded subunits during assembly (PMID:11937507, PMID:19185523). Assembly is gated by the phosphorylation state of serine 55: phosphomimetic substitutions block complex I assembly and activity, and an S55A knock-in mouse shows ~50% complex I deficiency with age-dependent Purkinje neuron degeneration, altered energy expenditure, and disturbed heme metabolism (PMID:17931954, PMID:28506826). Missense mutations including p.Gly8Arg, p.Arg37Ser, and G32R cause complex I deficiency by compromising assembly/stability (PMID:17262856, PMID:19185523). NDUFA1 transcription is controlled by CREB1, and its expression links mitochondrial complex I function to broader stress phenotypes: homocysteine suppresses NDUFA1 via CREB1 to drive ROS and cognitive impairment through the NAD+/Sirt1 axis (PMID:40624018), while NDUFA1 interaction with FSP1 contributes to ferroptosis resistance, an interaction lost when IDH1-R132H methylates the NDUFA1 promoter (PMID:39306640).

Mechanistic history

Synthesis pass · year-by-year structured walk · 10 steps
  1. 1999 High

    Established that the small MWFE polypeptide is not merely a passenger but is functionally essential for mammalian complex I activity, defining NDUFA1 as a required assembly subunit.

    Evidence Complementation of an NDUFA1-null Chinese hamster cell line with hamster cDNA, restoring rotenone-sensitive complex I activity

    PMID:10200266

    Open questions at the time
    • Did not resolve which structural region mediates the requirement
    • Mechanism of incorporation into the holoenzyme unaddressed
  2. 2002 High

    Mapped a discrete determinant (residues 39–46) governing species-specific nuclear–mitochondrial genome compatibility and showed MWFE is unstable without assembled mtDNA-encoded subunits, framing it as a co-assembly-dependent membrane subunit.

    Evidence Site-directed mutagenesis with null-cell complementation, Blue Native-PAGE, and activity assays

    PMID:11937507

    Open questions at the time
    • Physical contacts with specific mtDNA subunits not directly mapped
    • Structural basis of species incompatibility not resolved
  3. 2005 High

    Defined the protein's biogenesis logic: the N-terminal ~30 residues act simultaneously as targeting and stop-transfer signal, setting membrane orientation, explaining how a nuclear-encoded subunit is positioned within complex I.

    Evidence Mitochondrial import and topology assays with targeting-sequence mutagenesis and null-cell complementation

    PMID:16120368

    Open questions at the time
    • Import receptor/machinery dependencies not identified
    • Role of conserved Glu4 left functionally ambiguous
  4. 2007 High

    Identified serine-55 phosphorylation as a regulatory switch for complex I assembly, since phosphomimetic substitution fully blocks assembly while non-phosphorylatable S55A permits it.

    Evidence Systematic phosphosite mutagenesis with null-cell complementation, Blue Native-PAGE, and polarographic activity measurement

    PMID:17931954

    Open questions at the time
    • Kinase/phosphatase regulating S55 not identified
    • Physiological conditions altering S55 occupancy unknown
  5. 2007 Medium

    Linked NDUFA1 directly to human disease by showing patient missense mutations cause complex I deficiency through compromised assembly/stability rather than subcomplex accumulation.

    Evidence Patient DNA sequencing and 2D Blue Native-PAGE on patient fibroblasts (p.Gly8Arg, p.Arg37Ser)

    PMID:17262856

    Open questions at the time
    • Genotype–phenotype correlation across patients limited
    • Residue-level mechanism of destabilization not defined
  6. 2009 Medium

    Extended the disease mechanism by demonstrating a defined pathogenic mutation (G32R) reduces assembly/activity in a controlled null-cell system and confirmed physical interaction with mtDNA-encoded subunits.

    Evidence Introduction of G32R into NDUFA1-null hamster cells with assembly/activity assays and transmitochondrial cybrid analysis

    PMID:19185523

    Open questions at the time
    • Interaction partners among mtDNA subunits not individually resolved
    • Detailed interaction method not described
  7. 2017 High

    Validated S55 as a critical residue in vivo, showing partial complex I deficiency produces tissue- and sex-specific neurodegeneration and metabolic/heme phenotypes, connecting subunit function to organismal physiology.

    Evidence Ndufa1 S55A knock-in mouse with activity assays, calorimetry, Purkinje neuron histology, and metabolic/mRNA profiling

    PMID:28506826

    Open questions at the time
    • Cause of male-specific Purkinje vulnerability unexplained
    • Mechanistic link between complex I deficit and heme metabolism not established
  8. 2024 Medium

    Revealed a non-canonical role beyond the respiratory chain: NDUFA1 binds FSP1 to support ferroptosis resistance, with promoter methylation by IDH1-R132H suppressing NDUFA1 and severing this interaction.

    Evidence Co-IP interaction studies, promoter methylation analysis, knockdown/overexpression, and ROS/lipid peroxidation/cell death assays in renal tubular epithelial cells

    PMID:39306640

    Open questions at the time
    • Reciprocal validation and direct binding interface not shown
    • Whether ferroptosis role is separable from complex I function unclear
  9. 2024 Medium

    Proposed that lipid-exposed helices of NDUFA1 co-evolve with membrane cardiolipin unsaturation, explaining inter-kingdom incompatibility of the subunit.

    Evidence Molecular dynamics simulation plus in cellulo complementation with plant vs human variants and lipid manipulation (preprint)

    PMID:bio_10.1101_2024.07.01.601479

    Open questions at the time
    • Not peer-reviewed
    • Direct lipid–helix contacts in assembled complex I not experimentally resolved
  10. 2025 Medium

    Placed NDUFA1 in a regulatory circuit linking metabolic stress to mitochondrial dysfunction, showing homocysteine suppresses NDUFA1 via CREB1 to impair complex I and drive ROS and cognitive deficits through NAD+/Sirt1.

    Evidence In vivo rat homocysteine model with Ndufa1 overexpression/knockdown, complex I activity, mitochondrial morphology/mitophagy assays, behavioral tests, and CREB1 interaction studies

    PMID:40624018

    Open questions at the time
    • Direct CREB1 occupancy at the NDUFA1 promoter not fully resolved
    • Single-lab in vivo model

Open questions

Synthesis pass · forward-looking unresolved questions
  • The identity of the kinase/phosphatase controlling S55 and the structural mechanism by which NDUFA1 nucleates assembly with specific mtDNA-encoded subunits remain unresolved.
  • No enzyme assigned to S55 phosphorylation
  • No atomic-resolution map of NDUFA1 contacts within assembling complex I
  • Mechanistic relationship between respiratory and ferroptosis-resistance roles undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005198 structural molecule activity 3
Pathway
R-HSA-1430728 Metabolism 3
Partners
CREB1FSP1
Complex memberships
mitochondrial respiratory complex I

Evidence

Reading pass · 10 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1999 The MWFE polypeptide (NDUFA1) is essential for complex I activity in mammalian mitochondria. Complementation of a NDUFA1-null Chinese hamster cell line (CCL16-B2, which has <10% complex I activity) with hamster NDUFA1 cDNA restored rotenone-sensitive complex I activity to ~100% of parental levels. Complementation assay in NDUFA1-null Chinese hamster mutant cells (CCL16-B2) with hamster NDUFA1 cDNA; rotenone-sensitive complex I activity assay Proceedings of the National Academy of Sciences of the United States of America High 10200266
2002 The segment between amino acids 39–46 of MWFE (NDUFA1) is critical for species-specific compatibility between nuclear and mitochondrial genomes during complex I assembly. Human MWFE does not complement hamster null cells; substitutions in this region can convert the inactive human protein into a partially active one. Mutations R50K or short C-terminal deletions abolish activity. In the absence of MWFE, no high molecular weight complex I is detectable by Blue Native-PAGE. MWFE itself is unstable without assembled mtDNA-encoded integral membrane proteins. Site-directed mutagenesis, complementation of NDUFA1-null hamster cells, Blue Native-PAGE, enzyme activity assays The Journal of biological chemistry High 11937507
2004 The first ~30 amino acids of MWFE (NDUFA1) constitute a minimal mitochondrial targeting sequence that also functions as a stop-transfer signal, establishing the protein's orientation in the inner membrane and within complex I. A conserved glutamate at position 4 is atypical of a targeting signal but is not essential for MWFE function. The membrane anchor of MWFE cannot be functionally replaced by that from another complex I subunit. Import assays into mitochondria, topology/orientation experiments, mutagenesis of targeting sequence, complementation in null cells Mitochondrion High 16120368
2007 Phosphorylation of MWFE (NDUFA1) at serine 55 is functionally significant for complex I assembly. Substitution of S55 with glutamate (phosphomimetic), glutamine, or aspartate completely blocked complex I assembly and abolished activity, whereas S55A substitution permitted assembly. This indicates that the phosphorylation state of S55 critically regulates complex I assembly and function. Site-directed mutagenesis of phosphorylation sites, complementation of NDUFA1-null Chinese hamster cell lines, Blue Native-PAGE, polarographic complex I activity measurement The international journal of biochemistry & cell biology High 17931954
2007 Missense mutations p.Gly8Arg and p.Arg37Ser in NDUFA1 cause complex I deficiency. 2D Blue Native-PAGE analysis of patient fibroblasts showed decreased levels of intact complex I without accumulation of lower molecular weight subcomplexes, indicating compromised complex I assembly and/or stability. Sequencing of patient DNA, PCR-RFLP confirmation, 2D Blue Native-PAGE on patient fibroblasts Annals of neurology Medium 17262856
2009 The NDUFA1 G32R mutation causes a substantial decrease in complex I assembly and activity when introduced into a NDUFA1-null hamster cell line. MWFE protein interacts with mtDNA-encoded complex I subunits. Introduction of G32R mutation into NDUFA1-null hamster cell line; complex I assembly and activity assays; transmitochondrial cybrid analysis Molecular genetics and metabolism Medium 19185523
2017 An S55A knock-in mouse model (Ndufa1S55A) shows systemic ~50% partial complex I deficiency in both sexes, age-dependent Purkinje neuron degeneration in males, reduced respiratory exchange ratio, reduced body heat production, hypoactivity, and altered heme metabolism (reduced heme levels, altered Fech and Hmox1 mRNA expression). This establishes NDUFA1 S55 as a critical residue for complex I assembly/stability in vivo. Homologous recombination knock-in mouse model (S55A), complex I activity assays, respiratory exchange ratio measurement, calorimetry, histology of Purkinje neurons, metabolic profiling of brain/liver/serum, mRNA expression analysis Neurochemistry international High 28506826
2024 NDUFA1 physically interacts with FSP1 (ferroptosis suppressor protein 1), and this interaction contributes to resistance against cisplatin-induced tubular epithelial cell death. IDH1-R132H mutation increases methylation of the NDUFA1 promoter, suppressing its transcription and translation, which disrupts the NDUFA1–FSP1 interaction, leading to ROS accumulation, lipid peroxidation, and ferroptosis. Co-immunoprecipitation/interaction studies, promoter methylation analysis, NDUFA1 knockdown/overexpression, ROS and lipid peroxidation assays, cell death assays in renal tubular epithelial cells Cell death and differentiation Medium 39306640
2025 Homocysteine suppresses Ndufa1 expression by interfering with its transcription factor Creb1, reducing complex I assembly and activity, leading to increased ROS in rat hippocampus. Upregulation of Ndufa1 reversed homocysteine-induced mitochondrial morphology defects, impaired biogenesis, defective mitophagy, and cognitive impairment, establishing Ndufa1 as a molecular switch linking homocysteine to mitochondrial dysfunction via the NAD+/Sirt1 pathway. In vivo rat model with homocysteine treatment, Ndufa1 overexpression/knockdown, complex I activity assays, ROS measurement, mitochondrial morphology analysis, mitophagy assays, cognitive behavioral tests, NAD+/Sirt1 pathway analysis, transcription factor (Creb1) interaction studies Cell death & disease Medium 40624018
2024 Lipid-exposed helices of NDUFA1 (Complex I subunit) undergo inter-kingdom sequence divergence driven by differences in cardiolipin fatty acid unsaturation between human and plant (Arabidopsis) inner mitochondrial membranes. Molecular dynamics simulations and in cellulo assays demonstrated that plant-specific NDUFA1 IMM-exposed helices are incompatible with human cells, and plant-specific unsaturated fatty acids trigger complex I instability in human cells. Molecular dynamics simulation, in cellulo complementation assays with plant vs. human NDUFA1 variants, lipid manipulation experiments bioRxivpreprint Medium bio_10.1101_2024.07.01.601479

Source papers

Stage 0 corpus · 16 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2007 X-linked NDUFA1 gene mutations associated with mitochondrial encephalomyopathy. Annals of neurology 109 17262856
2009 A novel NDUFA1 mutation leads to a progressive mitochondrial complex I-specific neurodegenerative disease. Molecular genetics and metabolism 77 19185523
1999 The NDUFA1 gene product (MWFE protein) is essential for activity of complex I in mammalian mitochondria. Proceedings of the National Academy of Sciences of the United States of America 76 10200266
2002 Species-specific and mutant MWFE proteins. Their effect on the assembly of a functional mammalian mitochondrial complex I. The Journal of biological chemistry 54 11937507
2007 Investigations of the potential effects of phosphorylation of the MWFE and ESSS subunits on complex I activity and assembly. The international journal of biochemistry & cell biology 34 17931954
2005 Downregulation of NDUFA1 and other oxidative phosphorylation-related genes is a consistent feature of basal cell carcinoma. Experimental dermatology 28 15854127
2024 The IDH1-R132H mutation aggravates cisplatin-induced acute kidney injury by promoting ferroptosis through disrupting NDUFA1 and FSP1 interaction. Cell death and differentiation 27 39306640
2014 New MT-ND6 and NDUFA1 mutations in mitochondrial respiratory chain disorders. Annals of clinical and translational neurology 22 25356405
2011 Heterozygous mutation in the X chromosomal NDUFA1 gene in a girl with complex I deficiency. Molecular genetics and metabolism 18 21596602
2018 Leigh syndrome with spinal cord involvement due to a hemizygous NDUFA1 mutation. Brain & development 16 29506883
2004 Import and orientation of the MWFE protein in mitochondrial NADH-ubiquinone oxidoreductase. Mitochondrion 11 16120368
2022 NDUFA1 p.Gly32Arg variant in early-onset dementia. Neurobiology of aging 10 35131137
2017 An X-chromosome linked mouse model (Ndufa1S55A) for systemic partial Complex I deficiency for studying predisposition to neurodegeneration and other diseases. Neurochemistry international 9 28506826
2001 Sequence variations in the NDUFA1 gene encoding a subunit of complex I of the respiratory chain. Journal of inherited metabolic disease 8 11286378
2025 Identification of NDUFV2, NDUFS7, OPA1, and NDUFA1 as biomarkers for Alzheimer's disease: Insights from oxidative stress and mitochondrial dysfunction in the hippocampus. Journal of Alzheimer's disease : JAD 4 40329774
2025 Homocysteine interferes with Ndufa1 leading to mitochondrial dysfunction through repression of the NAD+/Sirt1 pathway in the brain: a possible link between hyperhomocysteinemia and neurodegeneration. Cell death & disease 3 40624018

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