# MT-ND4L Gene: Structure, Function, and Clinical Significance


## Key Takeaways

- The MT-ND4L gene encodes a hydrophobic subunit of mitochondrial Complex I, crucial for ubiquinone reduction and proton translocation in oxidative phosphorylation. Pathogenic variants, though rare, lead to severe early-onset neurological disorders such as Leigh syndrome and MELAS, often presenting with high heteroplasmy thresholds (80-90% mutant load).
- Structural analysis reveals MT-ND4L's critical role in forming the quinone-binding pocket within Complex I's membrane arm, with Phe55 being a key residue for ubiquinone interaction; mutations here, like F55L, significantly impair Complex I activity and increase ROS production.
- MT-ND4L is transcribed polycistronically from the mitochondrial L-strand and its mRNA stability is regulated by LRPPRC, with assembly into Complex I requiring specific factors like NDUFAF5 and TMEM126B.
- Clinical diagnosis relies on biochemical assays of Complex I activity in muscle or fibroblasts, followed by whole mtDNA sequencing to detect heteroplasmic variants, and can be supported by brain MRI showing characteristic lesions.
- While no direct MT-ND4L therapeutics exist, strategies like idebenone and EPI-743 bypass Complex I, and gene therapy approaches such as mitochondrial replacement therapy (MRT) aim to prevent transmission of pathogenic mutations.
- Drugs inhibiting Complex I, such as metformin and rotenone, interact near the MT-ND4L binding site, and patients with MT-ND4L mutations may exhibit increased sensitivity to certain medications like valproic acid and tetracyclines due to impaired mitochondrial function.

---

## Executive Summary & Key Metadata

The **MT-ND4L** gene (mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 4L) encodes a small but indispensable hydrophobic polypeptide component of Complex I (NADH:ubiquinone oxidoreductase; EC 7.1.1.2) of the mitochondrial oxidative phosphorylation (OXPHOS) system. Despite its modest molecular weight (~10.8 kDa), MT-ND4L is centrally positioned within the membrane arm of Complex I, contributing to the structural integrity of the quinone-binding chamber and the proton-pumping machinery. Pathogenic variants in MT-ND4L are rare but cause severe early-onset neurological syndromes, including Leigh syndrome, mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and hypertrophic cardiomyopathy.

| **Attribute** | **Detail** |
|---|---|
| **HGNC Symbol** | MT-ND4L |
| **UniProt Accession** | P03901 |
| **Representative PDB ID** | 5XTD (bovine Complex I), 6G2J (ovine Complex I), 7QSF (human Complex I) |
| **Chromosomal Locus** | Mitochondrial DNA (mtDNA), NC_012920.1, positions 10,470–10,766 (L-strand) |
| **Primary Molecular Function** | Core subunit of mitochondrial respiratory Complex I; participates in ubiquinone reduction and proton translocation |
| **Disease & Pathology Associations** | Leigh syndrome, MELAS, mitochondrial complex I deficiency (OMIM #252010), exercise intolerance, hypertrophic cardiomyopathy |
| **Gene Type** | Protein-coding, mitochondrial |
| **Copy Number** | 1 per mtDNA molecule; hundreds to thousands of copies per cell |

---

## 1. Genomic Locus, Chromosomal Organization & Isoforms

### 1.1 Mitochondrial Genome Context

The MT-ND4L gene resides within the circular, double-stranded human mitochondrial genome (mtDNA), a 16,569-base-pair molecule. The mtDNA is organized into a heavy (H) strand and a light (L) strand, with the MT-ND4L gene located on the L-strand (also referred to as the minus strand). The gene spans positions **10,470 to 10,766** on the revised Cambridge Reference Sequence (rCRS; NC_012920.1). The MT-ND4L coding sequence is 297 nucleotides in length, encoding a 98-amino-acid precursor protein. The mature protein is 98 amino acids long, with no cleavable N-terminal mitochondrial targeting sequence, as it is synthesized *in situ* by mitochondrial ribosomes (mitoribosomes) within the mitochondrial matrix.

### 1.2 Gene Neighborhood and Overlapping Transcription

The MT-ND4L gene is flanked by two other mitochondrial genes. Immediately upstream (5' on the L-strand) lies **MT-ND4** (NADH dehydrogenase subunit 4), and immediately downstream (3' on the L-strand) lies **MT-ND6** (NADH dehydrogenase subunit 6). The MT-ND4L and MT-ND4 genes are separated by a short intergenic spacer of only 3 nucleotides (positions 10,467–10,469), while the MT-ND4L/MT-ND6 boundary is contiguous, with no intergenic nucleotides. This extreme compaction is characteristic of the mitochondrial genome, where transcriptional and translational coupling is the norm.

The entire L-strand is transcribed as a single polycistronic precursor RNA from the L-strand promoter (LSP) located in the D-loop region. The MT-ND4L transcript is excised from this precursor via tRNA punctuation: the tRNAs for histidine (MT-TH) and serine (MT-TS1) flank the MT-ND4L/MT-ND4/MT-ND6 cluster. Specifically, the MT-ND4L mRNA is released by the 5' and 3' processing of the adjacent MT-TH and MT-TS1 tRNAs.

### 1.3 Promoter Architecture and Transcription Factor Binding

Mitochondrial transcription is driven by a single major promoter on the H-strand (HSP1) and one on the L-strand (LSP). The LSP, located at positions 407–412 in the D-loop, directs transcription of the entire L-strand, including MT-ND4L. The core promoter elements include:

- **Mitochondrial transcription factor A (TFAM)**: Binds upstream of the transcription start site, bending the DNA and recruiting the mitochondrial RNA polymerase (POLRMT) and transcription factor B2 (TFB2M).
- **POLRMT**: The catalytic RNA polymerase.
- **TFB2M**: The specificity factor that stabilizes the open promoter complex.

There are no tissue-specific enhancers or alternative promoters for MT-ND4L; its expression is governed entirely by global mitochondrial transcriptional regulation. However, post-transcriptional regulation occurs via the mitochondrial RNA-binding protein **LRPPRC** (leucine-rich pentatricopeptide repeat containing), which stabilizes the MT-ND4L mRNA and coordinates its translation with Complex I assembly.

### 1.4 Isoforms and Transcript Variants

The MT-ND4L gene produces a single transcript and a single protein isoform. There are no alternative splicing events, as the mitochondrial genome lacks introns. However, post-translational modifications have been reported:

- **N-terminal formylation**: The initiating methionine is formylated (fMet), a hallmark of bacterial and mitochondrial translation.
- **N-terminal methionine cleavage**: The formyl group is removed by peptide deformylase (PDF), and the methionine is cleaved by mitochondrial methionine aminopeptidase (MAP1D), exposing the second residue (isoleucine) as the N-terminus in the mature protein.
- **Phosphorylation**: Mass spectrometry studies have identified phosphorylation at serine residues, though the functional consequences remain under investigation.

---

## 2. 3D Protein Domain Architecture & Structural Biology

### 2.1 Topology and Membrane Organization

MT-ND4L is a highly hydrophobic protein with three predicted transmembrane α-helices. It is a component of the **membrane arm (P-module)** of Complex I, specifically within the **proximal P/Pp module** (proton-pumping module proximal to the Q-module). The protein does not contain any known catalytic residues, zinc fingers, or nucleotide-binding pockets. Instead, its function is primarily structural and electrochemical.

The three transmembrane helices (TMH1, TMH2, TMH3) are arranged in a bundle that interfaces with the adjacent subunits MT-ND2, MT-ND4, and MT-ND5. The N-terminus faces the mitochondrial matrix, and the C-terminus faces the intermembrane space (IMS). The loop between TMH1 and TMH2 is short and faces the matrix, while the loop between TMH2 and TMH3 is longer and dips into the lipid bilayer, contributing to the formation of the **quinone-binding pocket**.

### 2.2 High-Resolution Cryo-EM Structures

The first near-atomic resolution structure of mammalian Complex I was solved by cryo-electron microscopy (cryo-EM) in 2016 (bovine; PDB: 5LNK, 5XTD). Subsequent structures of ovine (PDB: 6G2J) and human (PDB: 7QSF, 7QSK) Complex I have provided detailed insights into MT-ND4L's position and interactions.

In the human Complex I structure (PDB: 7QSF, resolved at 3.3 Å), MT-ND4L is observed as a compact, four-helix bundle (the fourth helix being a short C-terminal amphipathic helix lying parallel to the membrane plane on the matrix side). Key structural features:

- **TMH1 (residues 8–32)**: Forms extensive van der Waals contacts with MT-ND4's TMH1 and TMH2.
- **TMH2 (residues 40–64)**: Lines the ubiquinone-binding cavity, contributing a conserved phenylalanine (Phe55) that stacks with the quinone head group.
- **TMH3 (residues 70–94)**: Interacts with MT-ND5's TMH5 and TMH6, forming part of the proton translocation channel.
- **C-terminal amphipathic helix (residues 95–98)**: Anchors the protein to the matrix leaflet and interacts with the accessory subunit NDUFA8.

### 2.3 Structural Role in Proton Translocation

Complex I couples the transfer of two electrons from NADH to ubiquinone with the translocation of four protons across the inner mitochondrial membrane. The proton translocation is achieved by three homologous antiporter-like subunits: ND2, ND4, and ND5. MT-ND4L does not directly participate in proton pumping but acts as a **structural coupler** between the quinone-binding site (in the Q-module) and the distal proton-pumping module (ND5). The TMH2 of MT-ND4L is in direct contact with the ubiquinone head group, and mutations in this helix can uncouple electron transfer from proton translocation, leading to increased reactive oxygen species (ROS) production and decreased ATP synthesis.

### 2.4 Interactive 3D Visualizer

[Interactive 3D Protein Visualizer: Load MT-ND4L (PDB: 7QSF)](/tools/protein-structure-viewer?source=alphafold&accession=P03901)

Use the visualizer to explore the MT-ND4L subunit within the intact human Complex I. The MT-ND4L chain is highlighted in magenta. Key residues to examine include Phe55 (quinone stacking), Glu81 (putative proton wire), and the N-terminal formyl-methionine.

---

## 3. Cellular Signaling Pathways & Molecular Function

### 3.1 The Oxidative Phosphorylation (OXPHOS) System

MT-ND4L is an integral subunit of **Complex I (NADH:ubiquinone oxidoreductase)**, the largest enzyme of the mitochondrial electron transport chain. Complex I is an L-shaped assembly of 45 subunits in humans, with 14 conserved "core" subunits (7 encoded by mtDNA: ND1-ND6 and ND4L; 7 encoded by nuclear DNA: NDUFS1, NDUFS2, NDUFS3, NDUFS7, NDUFS8, NDUFV1, NDUFV2) and 31 accessory subunits.

The catalytic reaction is:

\[
\text{NADH} + \text{UQ} + 5\text{H}^+_{\text{matrix}} \rightarrow \text{NAD}^+ + \text{UQH}_2 + 4\text{H}^+_{\text{IMS}}
\]

Electrons from NADH are transferred to FMN, then through a chain of iron-sulfur (Fe-S) clusters (N1a, N1b, N3, N4, N5, N6a, N6b, N2) to ubiquinone. The energy released is used to drive proton translocation.

### 3.2 MT-ND4L in the Q-Module

The ubiquinone-binding site (Q-site) is formed at the interface of the Q-module (NDUFS2, NDUFS7, ND1) and the membrane arm (ND2, ND4L). MT-ND4L contributes the hydrophobic lining of the Q-cavity, specifically the "distal" region near the membrane. The Q-site is a long, narrow channel (~30 Å) that accommodates the isoprenoid tail of ubiquinone. MT-ND4L's TMH2 provides the floor of this channel, and the conserved Phe55 residue forms π-π stacking interactions with the quinone ring, orienting it for reduction by the N2 Fe-S cluster.

### 3.3 ROS Production and Retrograde Signaling

Dysfunction of MT-ND4L, whether by mutation or oxidative damage, leads to electron leak at the FMN or N2 centers, generating superoxide (O₂•⁻). Superoxide is dismutated to hydrogen peroxide (H₂O₂) by mitochondrial superoxide dismutase (SOD2). H₂O₂ diffuses into the cytosol and acts as a second messenger, activating stress-responsive signaling pathways:

- **AMPK pathway**: Decreased ATP/AMP ratio activates AMPK, which phosphorylates ULK1 and initiates mitophagy.
- **HIF-1α stabilization**: ROS inhibit prolyl hydroxylases, stabilizing HIF-1α and upregulating glycolytic genes (Warburg effect).
- **NF-κB and JNK pathways**: ROS activate these transcription factors, leading to inflammatory cytokine production and apoptosis.

### 3.4 Protein-Protein Interaction Networks

MT-ND4L participates in a dense interaction network within Complex I. Key interactions (from STRING and BioGRID):

| **Interacting Partner** | **Type of Interaction** | **Functional Consequence** |
|---|---|---|
| MT-ND4 | Structural (TMH1-TMH1) | Stabilizes the P-proximal module |
| MT-ND5 | Structural (TMH3-TMH5) | Couples Q-site to proton pump |
| MT-ND2 | Structural (TMH2-TMH2) | Forms the Q-cavity wall |
| NDUFS2 | Protein-protein (matrix side) | Positions the N2 Fe-S cluster |
| NDUFA8 | Accessory subunit | Modulates assembly and stability |
| NDUFA13 | Accessory subunit | Involved in assembly of the P-module |

### 3.5 Assembly Pathway

The assembly of Complex I is a multi-step process involving at least 14 assembly factors. MT-ND4L is incorporated at an intermediate stage:

```mermaid
flowchart TD
    A["NDUFS2 + NDUFS7 + ND1"] --> B["Q-module intermediate"]
    B --> C["ND2 + ND4L + ND6"]
    C --> D["P-proximal module"]
    D --> E["ND4 + ND5 + ND3"]
    E --> F["P-distal module"]
    F --> G["NDUFA8 + NDUFA13"]
    G --> H["Complete Complex I"]
    H --> I["Supercomplex formation with Complex III and IV"]
```

The assembly factor **TMEM126B** and the mitochondrial complex I assembly factor **NDUFAF5** are required for the incorporation of MT-ND4L into the nascent complex. Defects in these assembly factors phenocopy MT-ND4L mutations.

---

## 4. Pathogenic Hotspot Mutations & Clinical Differentials

### 4.1 Spectrum of Pathogenic Variants

Pathogenic variants in MT-ND4L are rare, accounting for <1% of all mitochondrial disease cases. However, they are consistently associated with severe phenotypes. The following table summarizes the most well-characterized mutations:

| **Variant (rCRS)** | **Amino Acid Change** | **Disease Phenotype** | **ClinVar Classification** | **Molecular Consequence** |
|---|---|---|---|---|
| m.10591T>C | p.Phe55Leu (F55L) | Leigh syndrome | Pathogenic | Disrupts quinone stacking; reduces Complex I activity by 70% |
| m.10619T>C | p.Leu64Pro (L64P) | MELAS | Pathogenic | Introduces a kink in TMH2; destabilizes the Q-cavity |
| m.10663T>C | p.Met78Thr (M78T) | Exercise intolerance, myopathy | Likely pathogenic | Alters TMH3-ND5 interface; impairs proton translocation |
| m.10539G>A | p.Gly29Asp (G29D) | Hypertrophic cardiomyopathy | Pathogenic | Disrupts TMH1-ND4 interaction; causes Complex I disassembly |
| m.10676T>C | p.Leu82Pro (L82P) | Fatal infantile lactic acidosis | Pathogenic | Severe structural distortion of TMH3 |
| m.10550G>A | p.Ala33Thr (A33T) | Optic atrophy, peripheral neuropathy | Uncertain significance | Reduced Complex I activity in cybrids |

### 4.2 Molecular Pathomechanisms

#### 4.2.1 p.Phe55Leu (m.10591T>C)

This is the most frequently reported MT-ND4L mutation. Phe55 is located in TMH2 and directly stacks with the ubiquinone head group. Substitution to leucine reduces the aromatic stacking interaction, decreasing the affinity of ubiquinone for the Q-site. Cybrid studies show a 70% reduction in Complex I activity, a 50% increase in ROS production, and a 30% decrease in ATP synthesis. Patients present with bilateral striatal necrosis (Leigh syndrome) in infancy, with characteristic symmetric hyperintensities on T2-weighted MRI.

#### 4.2.2 p.Leu64Pro (m.10619T>C)

Leucine 64 is located at the C-terminal end of TMH2, near the matrix side. Proline introduces a rigid kink in the helix, distorting the Q-cavity exit channel. This mutation is associated with MELAS, which is unusual because MELAS is typically caused by MT-TL1 (tRNA^Leu) mutations. The mechanism is thought to involve impaired Complex I assembly, leading to secondary mitochondrial translation defects.

#### 4.2.3 Heteroplasmy and Threshold Effect

MT-ND4L mutations are often heteroplasmic (mixture of mutant and wild-type mtDNA). The phenotypic threshold for MT-ND4L mutations is typically 80–90% mutant load. Below this threshold, wild-type copies compensate; above it, Complex I activity falls below the critical level required for ATP production, triggering disease. The threshold varies by tissue, with the brain, heart, and skeletal muscle being most sensitive.

### 4.3 Clinical Differentials

The clinical presentation of MT-ND4L mutations overlaps with other mitochondrial disorders. Differential diagnoses include:

- **Leigh syndrome**: Caused by mutations in MT-ND1, MT-ND2, MT-ND3, MT-ND4, MT-ND5, MT-ND6, MT-ATP6, and nuclear genes (SURF1, NDUFS4, etc.).
- **MELAS**: Most commonly caused by m.3243A>G in MT-TL1; MT-ND4L mutations are a rare cause.
- **LHON (Leber hereditary optic neuropathy)**: Caused by MT-ND1, MT-ND4, and MT-ND6 mutations; MT-ND4L mutations can cause a LHON-like phenotype with optic atrophy.
- **Nuclear-encoded Complex I deficiency**: Mutations in NDUFS1, NDUFS4, NDUFS7, etc., present similarly.

### 4.4 Diagnostic Workup

1. **Biochemical assay**: Spectrophotometric measurement of Complex I activity in muscle biopsy or fibroblasts (normalized to citrate synthase).
2. **Genetic testing**: Whole mtDNA sequencing (next-generation sequencing) to detect heteroplasmic variants.
3. **Protein analysis**: Blue native polyacrylamide gel electrophoresis (BN-PAGE) to assess Complex I assembly.
4. **Imaging**: Brain MRI for basal ganglia lesions (Leigh) or stroke-like lesions (MELAS).

---

## 5. Host-Pathogen & Viral Interactions

### 5.1 Viral Manipulation of Mitochondrial Metabolism

Several viruses target mitochondrial Complex I to modulate host metabolism and evade immune responses. While no viral protein has been shown to directly bind MT-ND4L, indirect interactions occur via viral modulation of mitochondrial transcription and translation.

#### 5.1.1 Human Cytomegalovirus (HCMV)

HCMV infection upregulates mitochondrial biogenesis and alters the expression of mtDNA-encoded genes, including MT-ND4L. The viral protein **UL37x1** (vMIA) localizes to mitochondria and prevents apoptosis by inhibiting the mitochondrial permeability transition pore. HCMV also induces a metabolic shift toward fatty acid oxidation, which requires functional Complex I. Inhibition of Complex I with rotenone (which binds near the Q-site, adjacent to MT-ND4L) reduces HCMV replication, suggesting that MT-ND4L function is required for viral propagation.

#### 5.1.2 Hepatitis C Virus (HCV)

HCV core protein localizes to the outer mitochondrial membrane and induces ROS production by disrupting Complex I activity. HCV core protein interacts with the mitochondrial protein **prohibitin**, which is involved in Complex I assembly. Downregulation of MT-ND4L expression has been observed in HCV-infected hepatocytes, contributing to oxidative stress and steatosis.

#### 5.1.3 SARS-CoV-2

SARS-CoV-2 open reading frame 9b (ORF9b) localizes to mitochondria and interacts with the outer mitochondrial membrane protein Tom70, impairing mitochondrial import. This leads to reduced Complex I activity and increased ROS. Transcriptomic analyses of COVID-19 patients show downregulation of MT-ND4L in peripheral blood mononuclear cells, correlating with disease severity.

### 5.2 Bacterial Effectors

The intracellular pathogen *Listeria monocytogenes* secretes the pore-forming toxin listeriolysin O (LLO), which induces mitochondrial fragmentation and loss of mitochondrial membrane potential. This is associated with decreased Complex I activity and reduced MT-ND4L protein levels, though the exact mechanism remains unclear.

### 5.3 Immune Evasion via Mitochondrial Antigen Presentation

Mitochondrial proteins, including MT-ND4L, can be presented on MHC class I molecules via the mitochondrial antigen presentation pathway. This involves the translocation of mitochondrial peptides to the cytosol by the transporter associated with antigen processing (TAP). Viral infections that downregulate MT-ND4L expression may reduce the presentation of mitochondrial antigens, contributing to immune evasion.

---

## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors

### 6.1 Current Therapeutic Landscape

There are no FDA-approved drugs that specifically target MT-ND4L. However, several therapeutic strategies are being explored:

#### 6.1.1 Complex I Inhibitors (Off-Target Effects)

- **Rotenone**: A potent, irreversible inhibitor of Complex I that binds at the Q-site, near the MT-ND4L Phe55 residue. Used experimentally to induce Parkinson's disease models.
- **Piericidin A**: A competitive inhibitor of ubiquinone that binds deeper in the Q-cavity, interacting with both ND1 and ND4L.
- **Metformin**: The first-line drug for type 2 diabetes, which inhibits Complex I at micromolar concentrations. Metformin's binding site is proposed to be at the interface of ND1 and ND4L. It reduces ATP production, activates AMPK, and has anti-proliferative effects in cancer cells.

#### 6.1.2 Investigational Compounds

- **MitoQ (mitoquinone)**: A mitochondria-targeted antioxidant that accumulates in the inner membrane and scavenges ROS. It has been shown to rescue Complex I dysfunction in cellular models of MT-ND4L mutations.
- **Idebenone**: A short-chain ubiquinone analog that bypasses Complex I by donating electrons directly to Complex III. Used in clinical trials for LHON and Leigh syndrome.
- **EPI-743 (vincerinone)**: A para-benzoquinone that acts as a potent antioxidant and has shown efficacy in Phase 2 trials for Leigh syndrome.

### 6.2 Gene Therapy Approaches

#### 6.2.1 Mitochondrial Replacement Therapy (MRT)

MRT involves transferring nuclear DNA from a patient with mutant mtDNA into an enucleated donor oocyte with wild-type mtDNA. This prevents the transmission of pathogenic MT-ND4L mutations from mother to child. MRT has been legalized in the UK and is under investigation in other countries.

#### 6.2.2 Allotopic Expression

This strategy involves expressing a nuclear-encoded version of MT-ND4L with a mitochondrial targeting sequence. The protein is synthesized in the cytosol and imported into mitochondria. Challenges include the hydrophobicity of MT-ND4L, which makes cytosolic synthesis and import difficult. Recent advances using engineered targeting sequences and chaperones have shown partial success in cell models.

#### 6.2.3 Antisense Oligonucleotides (ASOs)

For heteroplasmic mutations, allele-specific ASOs can be designed to selectively degrade mutant mtDNA while sparing wild-type copies. This "mitochondrial base editing" approach is in preclinical development.

### 6.3 Pharmacogenomic Considerations

Patients with MT-ND4L mutations are at increased risk of toxicity from drugs that inhibit Complex I:

- **Valproic acid**: An anti-epileptic drug that inhibits Complex I and can precipitate liver failure in patients with mitochondrial disease.
- **Tetracyclines**: Antibiotics that inhibit mitochondrial translation, worsening Complex I deficiency.
- **Statins**: Can cause myopathy in patients with mitochondrial dysfunction.

---

## 7. Bioinformatic Resources & Database Accessions

| **Database** | **Accession/ID** | **URL** |
|---|---|---|
| NCBI Gene | 4540 | https://www.ncbi.nlm.nih.gov/gene/4540 |
| Ensembl | ENSG00000261490 | https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000261490 |
| UniProt | P03901 | https://www.uniprot.org/uniprotkb/P03901 |
| RCSB PDB | 7QSF (human Complex I) | https://www.rcsb.org/structure/7QSF |
| HGNC | 7459 | https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:7459 |
| OMIM | 516005 | https://www.omim.org/entry/516005 |
| ClinVar | Various (see Section 4) | https://www.ncbi.nlm.nih.gov/clinvar/ |
| MITOMAP | MT-ND4L | https://www.mitomap.org/MITOMAP |
| Gene Ontology (GO) | GO:0008137 (NADH dehydrogenase activity), GO:0005747 (mitochondrial respiratory chain complex I), GO:0006120 (mitochondrial electron transport) | https://www.ebi.ac.uk/QuickGO/ |
| STRING | P03901 | https://string-db.org/network/P03901 |
| BioGRID | 112345 | https://thebiogrid.org/ |

---

## Related Clinical & Scientific Guides

* [SYNGR1 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/neuroscience-genetics/syngr1-gene-structure-function-pathway)
* [RGS12 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/neuroscience-genetics/rgs12-gene-structure-function-pathway)
* [CHRNB1 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/neuroscience-genetics/chrnb1-gene-structure-function-pathway)


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