MT-ND6

Last updated
ND6
Identifiers
Aliases ND6 , MTMT-NADH dehydrogenase, subunit 6 (complex I), NADH dehydrogenase subunit 6
External IDs OMIM: 516006 MGI: 102495 HomoloGene: 5022 GeneCards: ND6
Orthologs
SpeciesHumanMouse
Entrez

4541

17722

Ensembl

ENSG00000198695

ENSMUSG00000064368

UniProt

P03923

P03925

RefSeq (mRNA)

n/a

n/a

RefSeq (protein)

n/a

NP_904339

Location (UCSC) Chr M: 0.01 – 0.01 Mb Chr M: 0.01 – 0.01 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse
Location of the MT-ND6 gene on the L strand of the human mitochondrial genome. MT-ND6 is one of the seven NADH dehydrogenase mitochondrial genes (yellow boxes). Map of the human mitochondrial genome.svg
Location of the MT-ND6 gene on the L strand of the human mitochondrial genome. MT-ND6 is one of the seven NADH dehydrogenase mitochondrial genes (yellow boxes).

MT-ND6 is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 6 protein (ND6). [5] The ND6 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. [6] Variations in the human MT-ND6 gene are associated with Leigh's syndrome, Leber's hereditary optic neuropathy (LHON) and dystonia. [7]

Contents

Structure

The MT-ND6 gene is located in human mitochondrial DNA from base pair 14,149 to 14,673. [5] MT-ND6 is the only protein-coding gene located on the L-strand of the human mitogenome. [8]

The encoded protein is 18 kDa and composed of 172 amino acids. [9] [10] MT-ND6 is one of seven mitochondrial genes encoding subunits of the enzyme NADH dehydrogenase (ubiquinone), together with MT-ND1, MT-ND2, MT-ND3, MT-ND4, MT-ND4L, and MT-ND5. Also known as Complex I, this enzyme is the largest of the respiratory complexes. The structure is L-shaped with a long, hydrophobic transmembrane domain and a hydrophilic domain for the peripheral arm that includes all the known redox centres and the NADH binding site. MT-ND6 and the rest of the mitochondrially encoded subunits are the most hydrophobic of the subunits of Complex I and form the core of the transmembrane region. [6]

Function

The MT-ND6 product is a subunit of the respiratory chain Complex I that is believed to belong to the minimal assembly of core proteins required to catalyze NADH dehydrogenation and electron transfer to ubiquinone (coenzyme Q10). [11] Initially, NADH binds to Complex I and transfers two electrons to the isoalloxazine ring of the flavin mononucleotide (FMN) prosthetic arm to form FMNH2. The electrons are transferred through a series of iron-sulfur (Fe-S) clusters in the prosthetic arm and finally to coenzyme Q10 (CoQ), which is reduced to ubiquinol (CoQH2). The flow of electrons changes the redox state of the protein, resulting in a conformational change and pK shift of the ionizable side chain, which pumps four hydrogen ions out of the mitochondrial matrix. [6]

Clinical significance

A T → C mutation at the 14484 base pair in the MT-ND6 gene has been identified in people with Leber's hereditary optic neuropathy (LHON). This common MT-ND6 mutation is responsible for about 14 percent of all cases of LHON, and it is the most common cause of this disorder among people of French Canadian descent. This mutation changes a single amino acid in the NADH dehydrogenase 6 protein at position 64, from methionine to valine. The T14484C mutation is associated with a good long-term prognosis; affected people with this genetic change have a 37 percent to 65 percent chance of some visual recovery. Researchers are investigating how mutations in the MT-ND6 gene lead to Leber's hereditary optic neuropathy. These genetic changes appear to prevent Complex I from interacting normally with ubiquinone, which may affect the generation of ATP and may also increase the production within mitochondria of potentially harmful molecules called reactive oxygen species (ROS). It remains unclear, however, why the effects of these mutations are often limited to the nerve that relays visual information from the eye to the brain (the optic nerve). Additional genetic and environmental factors probably contribute to the vision loss and other medical problems associated with Leber hereditary optic neuropathy. [7]

A G → A mutation at the 14459 base pair in the MT-ND6 gene also has been identified in a small number of people with Leigh's syndrome, a progressive brain disorder that typically appears in infancy or early childhood. Affected children may experience vomiting, seizures, delayed development, muscle weakness, and problems with movement. Heart disease, kidney problems, and difficulty breathing can also occur in people with this disorder. This MT-ND6 G14459A mutation replaces the amino acid alanine with the amino acid valine at protein position 72 in the NADH-ubiquinone oxidoreductase chain 6 protein. This genetic change also has been found in people with LHON and a movement disorder called dystonia, which involves involuntary muscle contractions, tremors, and other uncontrolled movements. This mutation appears to disrupt the normal assembly or activity of complex I in mitochondria. It is not known, however, how this MT-ND6 gene alteration is related to the specific features of Leigh syndrome, LHON, or dystonia. It also remains unclear why a single mutation can cause such varied signs and symptoms in different people. [7]

Interactions

MT-ND6 interacts with the NADH dehydrogenase [ubiquinone] iron-sulfur protein 3 (NDUFS3) and the ATP-dependent metalloprotease YME1L1. [5]

Related Research Articles

Homoplasmy Identity of organellar DNA sequences in a cell

Homoplasmy is a term used in genetics to describe a eukaryotic cell whose copies of mitochondrial DNA are all identical. In normal and healthy tissues, all cells are homoplasmic. Homoplasmic mitochondrial DNA copies may be normal or mutated; however, most mutations are heteroplasmic. It has been discovered, though, that homoplasmic mitochondrial DNA mutations may be found in human tumors.

Lebers hereditary optic neuropathy Mitochondrially inherited degeneration of retinal cells in human

Leber's hereditary optic neuropathy (LHON) is a mitochondrially inherited degeneration of retinal ganglion cells (RGCs) and their axons that leads to an acute or subacute loss of central vision; it predominantly affects young adult males. LHON is transmitted only through the mother, as it is primarily due to mutations in the mitochondrial genome, and only the egg contributes mitochondria to the embryo. LHON is usually due to one of three pathogenic mitochondrial DNA (mtDNA) point mutations. These mutations are at nucleotide positions 11778 G to A, 3460 G to A and 14484 T to C, respectively in the ND4, ND1 and ND6 subunit genes of complex I of the oxidative phosphorylation chain in mitochondria. Men cannot pass on the disease to their offspring.

MT-ND4 Mitochondrial gene coding for a protein involved in the respiratory chain

MT-ND4 is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 4 (ND4) protein. The ND4 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variations in the MT-ND4 gene are associated with age-related macular degeneration (AMD), Leber's hereditary optic neuropathy (LHON), mesial temporal lobe epilepsy (MTLE) and cystic fibrosis.

MT-ND2 Mitochondrial gene coding for a protein involved in the respiratory chain

MT-ND2 is a gene of the mitochondrial genome coding for the NADH dehydrogenase 2 (ND2) protein. The ND2 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variants of human MT-ND2 are associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Leigh's syndrome (LS), Leber's hereditary optic neuropathy (LHON) and increases in adult BMI.

MT-ND4L Mitochondrial gene coding for a protein involved in the respiratory chain

MT-ND4L is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 4L (ND4L) protein. The ND4L protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variants of human MT-ND4L are associated with increased BMI in adults and Leber's Hereditary Optic Neuropathy (LHON).

MT-ND3 Mitochondrial protein-coding gene whose product is involved in the respiratory chain

MT-ND3 is a gene of the mitochondrial genome coding for the NADH dehydrogenase 3 (ND3) protein. The ND3 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variants of MT-ND3 are associated with Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Leigh's syndrome (LS) and Leber's hereditary optic neuropathy (LHON).

MT-ND5 Mitochondrial gene coding for a protein involved in the respiratory chain

MT-ND5 is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 5 protein (ND5). The ND5 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variations in human MT-ND5 are associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) as well as some symptoms of Leigh's syndrome and Leber's hereditary optic neuropathy (LHON).

MT-ND1 Mitochondrial gene coding for a protein involved in the respiratory chain

MT-ND1 is a gene of the mitochondrial genome coding for the NADH-ubiquinone oxidoreductase chain 1 (ND1) protein. The ND1 protein is a subunit of NADH dehydrogenase, which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Variants of the human MT-ND1 gene are associated with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), Leigh's syndrome (LS), Leber's hereditary optic neuropathy (LHON) and increases in adult BMI.

Cytochrome c oxidase subunit I Enzyme of the respiratory chain encoded by the mitochondrial genome

Cytochrome c oxidase I (COX1) also known as mitochondrially encoded cytochrome c oxidase I (MT-CO1) is a protein that in humans is encoded by the MT-CO1 gene. In other eukaryotes, the gene is called COX1, CO1, or COI. Cytochrome c oxidase I is the main subunit of the cytochrome c oxidase complex. Mutations in MT-CO1 have been associated with Leber's hereditary optic neuropathy (LHON), acquired idiopathic sideroblastic anemia, Complex IV deficiency, colorectal cancer, sensorineural deafness, and recurrent myoglobinuria.

Cytochrome c oxidase subunit III Enzyme of the respiratory chain encoded by the mitochondrial genome

Cytochrome c oxidase subunit III (COX3) is an enzyme that in humans is encoded by the MT-CO3 gene. It is one of main transmembrane subunits of cytochrome c oxidase. Cytochrome c oxidase subunit III is also one of the three mitochondrial DNA (mtDNA) encoded subunits of respiratory complex IV. Variants of MT-CO3 have been associated with isolated myopathy, severe encephalomyopathy, Leber hereditary optic neuropathy, mitochondrial complex IV deficiency, and recurrent myoglobinuria.

NDUFS4

NADH dehydrogenase [ubiquinone] iron-sulfur protein 4, mitochondrial (NDUFS4) also known as NADH-ubiquinone oxidoreductase 18 kDa subunit is an enzyme that in humans is encoded by the NDUFS4 gene. This gene encodes an nuclear-encoded accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase. Complex I removes electrons from NADH and passes them to the electron acceptor ubiquinone. Mutations in this gene can cause mitochondrial complex I deficiencies such as Leigh syndrome.

NDUFV1

NADH dehydrogenase [ubiquinone] flavoprotein 1, mitochondrial (NDUFV1) is an enzyme that in humans is encoded by the NDUFV1 gene. The NDUFV1 gene encodes the 51-kD subunit of complex I of the mitochondrial respiratory chain. Defects in complex I are a common cause of mitochondrial dysfunction. Mitochondrial complex I deficiency is linked to myopathies, encephalomyopathies, and neurodegenerative disorders such as Parkinson's disease and Leigh syndrome.

NDUFS2

NADH dehydrogenase [ubiquinone] iron-sulfur protein 2, mitochondrial (NDUFS2) also known as NADH-ubiquinone oxidoreductase 49 kDa subunit is an enzyme that in humans is encoded by the NDUFS2 gene. The protein encoded by this gene is a core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase. Mutations in this gene are associated with mitochondrial complex I deficiency.

NADH dehydrogenase (ubiquinone), alpha 1

NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 1 is a protein that in humans is encoded by the NDUFA1 gene. The NDUFA1 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain. Mutations in the NDUFA1 gene are associated with mitochondrial Complex I deficiency.

NDUFS1 Protein-coding gene in the species Homo sapiens

NADH-ubiquinone oxidoreductase 75 kDa subunit, mitochondrial (NDUFS1) is an enzyme that in humans is encoded by the NDUFS1 gene. The encoded protein, NDUFS1, is the largest subunit of complex I, located on the inner mitochondrial membrane, and is important for mitochondrial oxidative phosphorylation. Mutations in this gene are associated with complex I deficiency.

NDUFV2

NADH dehydrogenase [ubiquinone] flavoprotein 2, mitochondrial (NDUFV2) is an enzyme that in humans is encoded by the NDUFV2 gene. The encoded protein, NDUFV2, is a subunit of complex I of the mitochondrial respiratory chain, which is located on the inner mitochondrial membrane and involved in oxidative phosphorylation. Mutations in this gene are implicated in Parkinson's disease, bipolar disorder, schizophrenia, and have been found in one case of early onset hypertrophic cardiomyopathy and encephalopathy.

NDUFS7

NADH dehydrogenase [ubiquinone] iron-sulfur protein 7, mitochondrial, also knowns as NADH-ubiquinone oxidoreductase 20 kDa subunit, Complex I-20kD (CI-20kD), or PSST subunit is an enzyme that in humans is encoded by the NDUFS7 gene. The NDUFS7 protein is a subunit of NADH dehydrogenase (ubiquinone) also known as Complex I, which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain.

NDUFS6

NADH dehydrogenase [ubiquinone] iron-sulfur protein 6, mitochondrial is an enzyme that in humans is encoded by the NDUFS6 gene.

NDUFB11

NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 11, mitochondrial is an enzyme that in humans is encoded by the NDUFB11 gene. NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 11 is an accessory subunit of the NADH dehydrogenase (ubiquinone) complex, located in the mitochondrial inner membrane. It is also known as Complex I and is the largest of the five complexes of the electron transport chain. NDUFB11 mutations have been associated with linear skin defects with multiple congenital anomalies 3 and mitochondrial complex I deficiency.

NDUFA11

NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 11 is an enzyme that in humans is encoded by the NDUFA11 gene. The NDUFA11 protein is a subunit of NADH dehydrogenase (ubiquinone), which is located in the mitochondrial inner membrane and is the largest of the five complexes of the electron transport chain Mutations in subunits of NADH dehydrogenase (ubiquinone), also known as Complex I, frequently lead to complex neurodegenerative diseases such as Leigh's syndrome. Mutations in this gene are associated with severe mitochondrial complex I deficiency.

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000198695 - Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000064368 - Ensembl, May 2017
  3. ↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. 1 2 3 "Entrez Gene: MT-ND6 NADH dehydrogenase subunit 6".
  6. 1 2 3 Donald Voet; Judith G. Voet; Charlotte W. Pratt (2013). "18". Fundamentals of biochemistry : life at the molecular level (4th ed.). Hoboken, NJ: Wiley. pp. 581–620. ISBN   9780470547847.
  7. 1 2 3 "MT-ND6". Genetics Home Reference. U.S. National Library of Medicine. Retrieved 23 March 2015.
  8. ↑ Anderson S, Bankier AT, Barrell BG, de Bruijn MH, Coulson AR, Drouin J, Eperon IC, Nierlich DP, Roe BA, Sanger F, Schreier PH, Smith AJ, Staden R, Young IG (April 1981). "Sequence and organization of the human mitochondrial genome". Nature. 290 (5806): 457–65. Bibcode:1981Natur.290..457A. doi:10.1038/290457a0. PMID   7219534. S2CID   4355527.
  9. ↑ Zong NC, Li H, Li H, Lam MP, Jimenez RC, Kim CS, Deng N, Kim AK, Choi JH, Zelaya I, Liem D, Meyer D, Odeberg J, Fang C, Lu HJ, Xu T, Weiss J, Duan H, Uhlen M, Yates JR, Apweiler R, Ge J, Hermjakob H, Ping P (October 2013). "Integration of cardiac proteome biology and medicine by a specialized knowledgebase". Circulation Research. 113 (9): 1043–53. doi:10.1161/CIRCRESAHA.113.301151. PMC   4076475 . PMID   23965338.
  10. ↑ "NADH-ubiquinone oxidoreductase chain 6". Cardiac Organellar Protein Atlas Knowledgebase (COPaKB).
  11. ↑ "MT-ND6 - NADH-ubiquinone oxidoreductase chain 6 - Homo sapiens (Human)". UniProt.org: a hub for protein information. The UniProt Consortium.

Further reading

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