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UQCRFS1 Gene
UQCRFS1 Gene
Overview
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">UQCRFS1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>UQCRFS1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Ubiquinol-Cytochrome c Reductase Core Protein 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>19q12</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>27089</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>191317</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000127540</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P31930</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>Mitochondrial complex III subunit (2Fe-2S protein)</td>
</tr>
<tr>
<td class="label">Tissue Expression</td>
<td>High in brain, heart, muscle</td>
</tr>
<tr>
<td class="label">Brain Region</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Cerebral Cortex</td>
<td>High</td>
</tr>
<tr>
<td class="label">Hippocampus</td>
<td>High</td>
</tr>
<tr>
<td class="label">Cerebellum</td>
<td>High</td>
</tr>
<tr>
<td class="label">Substantia Nigra</td>
<td>High</td>
</tr>
<tr>
<td class="label">Basal Ganglia</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Brainstem</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Approach</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">CoQ10</td>
<td>Electron carrier
UQCRFS1 Gene
Overview
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">UQCRFS1 Gene</th>
</tr>
<tr>
<td class="label">Gene Symbol</td>
<td>UQCRFS1</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Ubiquinol-Cytochrome c Reductase Core Protein 1</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>19q12</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>27089</td>
</tr>
<tr>
<td class="label">OMIM</td>
<td>191317</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000127540</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>P31930</td>
</tr>
<tr>
<td class="label">Protein Class</td>
<td>Mitochondrial complex III subunit (2Fe-2S protein)</td>
</tr>
<tr>
<td class="label">Tissue Expression</td>
<td>High in brain, heart, muscle</td>
</tr>
<tr>
<td class="label">Brain Region</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Cerebral Cortex</td>
<td>High</td>
</tr>
<tr>
<td class="label">Hippocampus</td>
<td>High</td>
</tr>
<tr>
<td class="label">Cerebellum</td>
<td>High</td>
</tr>
<tr>
<td class="label">Substantia Nigra</td>
<td>High</td>
</tr>
<tr>
<td class="label">Basal Ganglia</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Brainstem</td>
<td>Moderate</td>
</tr>
<tr>
<td class="label">Approach</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">CoQ10</td>
<td>Electron carrier</td>
</tr>
<tr>
<td class="label">MitoQ</td>
<td>Mitochondria-targeted antioxidant</td>
</tr>
<tr>
<td class="label">Idebenone</td>
<td>Complex III protectant</td>
</tr>
<tr>
<td class="label">Vitamin E</td>
<td>ROS scavenging</td>
</tr>
<tr>
<td class="label">Therapeutic</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">Ubiquinol (CoQ10)</td>
<td>Electron carrier, antioxidant</td>
</tr>
<tr>
<td class="label">MitoQ</td>
<td>Mitochondria-targeted CoQ10</td>
</tr>
<tr>
<td class="label">Idebenone</td>
<td>Synthetic CoQ10 analog</td>
</tr>
<tr>
<td class="label">EUK-134</td>
<td>Catalytic antioxidant</td>
</tr>
<tr>
<td class="label">Szeto-Schiller peptides</td>
<td>Mitochondrial antioxidants</td>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction</td>
</tr>
<tr>
<td class="label">UQCRFS1 (RISP)</td>
<td>Forms bc1 complex</td>
</tr>
<tr>
<td class="label">Cytochrome c1</td>
<td>Electron transfer</td>
</tr>
<tr>
<td class="label">Cytochrome b</td>
<td>Qo/Qi sites</td>
</tr>
<tr>
<td class="label">Iron-sulfur cluster</td>
<td>Catalytic center</td>
</tr>
<tr>
<td class="label">Rieske protein</td>
<td>Subunit assembly</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">10 edges</a></td>
</tr>
</table>
UQCRFS1 (Ubiquinol-Cytochrome c Reductase Core Protein 1), also known as Rieske iron-sulfur protein (RISP), is a nuclear-encoded mitochondrial protein that serves as a critical core component of complex III (cytochrome bc1 complex) in the electron transport chain[@craft2011]. The protein contains a 2Fe-2S iron-sulfur cluster that transfers electrons from ubiquinol to cytochrome c1, a key step in the Q-cycle that generates the proton gradient essential for ATP synthesis. UQCRFS1 is essential for oxidative phosphorylation and is implicated in various neurodegenerative diseases through mitochondrial dysfunction.
Structure and Function
Protein Structure
UQCRFS1 (274 amino acids) is a key component of the cytochrome bc1 complex:
- N-terminal transit peptide: Mitochondrial targeting sequence (cleaved after import)
- Rieske domain: Contains the 2Fe-2S cluster
- C-terminal helix: Anchors to the matrix side of the inner membrane
- Iron-sulfur cluster: [2Fe-2S] center with unique ligation (Cys/His)
The 2Fe-2S cluster is coordinated by:
- Two cysteine residues
- Two histidine residues
- Unique among iron-sulfur proteins
Catalytic Function in Complex III
UQCRFS1 is the heart of the Q-cycle in complex III[@giachin2016]:
- Generates semiquinone (Q•⁻) at Qo site
- Releases 2H⁺ to intermembrane space
- Electron transfers to cytochrome c
- Forms QH₂ at Qi site
This process creates the proton gradient (3-4 H⁺ pumped per electron pair).
The Q-Cycle Mechanism
Qo site Qi site
┌─────────────┐ ┌─────────────┐
│ │ │ │
QH₂ ──→│ UQCRFS1 │───cyt c1───cyt c ←───│ Q │
│ (2Fe-2S) │ ↓ │ (ox) │
│ │ │ │
└─────────────┘ └─────────────┘
↓ H⁺ ↓ H⁺
(intermembrane space) (intermembrane space)
Normal Function
Electron Transport Chain
UQCRFS1 is essential for complex III function[@wang2020]:
- Electron transfer: From ubiquinol to cytochrome c
- Proton pumping: 4 H⁺ per pair of electrons
- Ubiquinone cycling: Q-cycle mechanism
- ATP synthesis: Powers ATP synthase
Mitochondrial Respiration
In neurons, complex III supports:
- Oxidative phosphorylation: Primary ATP production
- NADH regeneration: Maintains NAD⁺/NADH ratio
- Calcium handling: Mitochondrial calcium uptake
- Synaptic energy: High energy demands of neurotransmission
Regulation of Apoptosis
UQCRFS1 plays a role in intrinsic apoptosis[@birk2011]:
- Cytochrome c release: Complex III can release cytochrome c
- ROS signaling: Elevated ROS triggers apoptosis
- Bcl-2 family interaction: Cross-talk with apoptotic proteins
Disease Associations
Mitochondrial Complex III Deficiency
Mutations in UQCRFS1 cause complex III deficiency[@ellis2011]:
- Encephalomyopathy: Brain and muscle involvement
- Lactic acidosis: Accumulation of lactate
- Failure to thrive: Growth impairment
- Myopathy: Muscle weakness
- Ataxia: Coordination problems
Leigh Syndrome
UQCRFS1 mutations can cause Leigh syndrome[@chen2012]:
- Progressive neurodegeneration: Characteristic brainstem lesions
- Bilateral basal ganglia involvement: Necrotic lesions
- Developmental regression: Loss of milestones
- Respiratory failure: Brainstem dysfunction
Parkinson's Disease
Complex III dysfunction is implicated in PD[@schapira2012]:
- Complex I deficiency: PD primarily affects complex I
- Compensatory complex III changes: Altered function
- ROS overproduction: From impaired electron transport
- Dopaminergic neuron vulnerability: Energy-demanding cells
Alzheimer's Disease
Mitochondrial complex III in AD[@moreira2010]:
- Complex III activity reduced: 20-40% decrease
- Electron transport impairment: Causes energy failure
- ROS production: Increased oxidative stress
- Amyloid-β interaction: Aβ impairs complex III
Other Neurodegenerative Conditions
- Amyotrophic Lateral Sclerosis (ALS): Mitochondrial dysfunction
- Huntington's Disease: Complex III alterations
- Leber's hereditary optic neuropathy: Complex I/III defects
Amyotrophic Lateral Sclerosis
Complex III dysfunction is observed in ALS and contributes to motor neuron degeneration. Studies have shown that UQCRFS1 activity is reduced in spinal cord tissue from ALS patients, and this reduction correlates with disease progression. The mechanisms include both sporadic dysfunction and genetic factors affecting complex III assembly[@gomez2017].
Huntington's Disease
In Huntington's disease, mutant huntingtin protein directly impairs mitochondrial function, including complex III activity. The decreased activity leads to:
- Enhanced ROS production
- Impaired energy metabolism
- Increased susceptibility to excitotoxicity
- Progressive neuronal dysfunction
Mechanism of Neurodegeneration
Energy Failure
Impaired complex III leads to[@sorrentino2016]:
- ATP depletion: Reduced oxidative phosphorylation
- NAD⁺ loss: Impaired metabolic function
- Ion gradient collapse: Cellular dysfunction
- Synaptic failure: Energy-dependent processes cease
Reactive Oxygen Species
Complex III is a major ROS source[@murphy2009]:
- Electron leak: At Qo site during Q-cycle
- Superoxide production: O₂⁻ generation
- Hydrogen peroxide: From dismutated superoxide
- Hydroxyl radicals: Most damaging (via Fenton)
Mitochondrial Dynamics
Quality control mechanisms fail[@van2012]:
- Fission/fusion imbalance: Altered mitochondrial morphology
- Mitophagy defects: Impaired clearance of damaged mitochondria
- Mitochondrial DNA mutations: Accumulate with age
Apoptotic Cascade
Cell death pathways activate[@czabot2011]:
- Cytochrome c release: Triggers apoptosome formation
- Caspase activation: Executioner caspases
- PARP cleavage: DNA repair failure
- Neurological symptoms: Resulting from neuron loss
Brain Expression
Regional Distribution
UQCRFS1 is expressed throughout the brain:
Cellular Localization
- Neurons: High expression in energy-demanding neurons
- Astrocytes: Moderate expression
- Oligodendrocytes: High (myelin production needs ATP)
- Microglia: Lower expression
Subcellular Distribution
Within neurons, UQCRFS1 is localized primarily to:
The distribution of UQCRFS1 along axons is particularly relevant for neurodegenerative diseases because axonal transport deficits precede cell body degeneration in both AD and PD[@bhat2021].
Therapeutic Targeting
Antioxidant Strategies
Emerging Therapeutic Approaches
Beyond traditional antioxidants, several novel approaches show promise:
Research into these approaches has accelerated due to advances in structural biology that have revealed the detailed mechanism of UQCRFS1 function.
Mitochondrial Modulation
- Complex III enhancers: Increase enzyme activity
- Electron transfer mediators: Improve function
- Gene therapy: Deliver functional UQCRFS1
Biomarkers and Diagnostics
The measurement of complex III activity in various tissues holds diagnostic potential:
- Skeletal muscle biopsy: Direct enzyme activity measurement
- Platelet mitochondria: Peripheral assessment of complex III function
- Fibroblast culture: Patient-specific functional studies
These approaches are particularly valuable for diagnosing mitochondrial complex III deficiency syndromes and for monitoring therapeutic response.
Metabolic Approaches
- NAD⁺ precursors: Support mitochondrial function
- Alpha-ketoglutarate: Metabolic intermediate
- Pyruvate supplementation: Energy substrate
Clinical Implications
Complex III dysfunction has significant clinical implications for neurodegenerative diseases. The progressive nature of mitochondrial dysfunction correlates with disease staging in both Alzheimer's and Parkinson's disease[@brandt2018]. In Alzheimer's disease, complex III activity shows a characteristic decline that parallels cognitive deterioration, with post-mortem studies revealing 30-50% reduction in complex III activity in affected brain regions[@manes2023].
The Rieske iron-sulfur protein (UQCRFS1) represents a particularly vulnerable node in the electron transport chain due to its unique iron-sulfur cluster that is susceptible to oxidative damage. Studies have shown that oxidative modifications to the 2Fe-2S cluster lead to enzymatic dysfunction that precedes clinical symptoms in mouse models of neurodegeneration[@park2024].
Recent Research Advances
Complex III and Synaptic Dysfunction
Recent research has revealed that complex III deficiency has profound effects on synaptic function beyond energy production. The electron transport chain supports synaptic vesicle recycling, neurotransmitter release, and dendritic spine maintenance. Studies in 2022 demonstrated that UQCRFS1 dysfunction leads to impaired synaptic plasticity and long-term potentiation deficits in hippocampal neurons[@zhang2022]. This finding has important implications for understanding memory deficits in Alzheimer's disease.
Alpha-Synuclein and Complex III
A significant research advance comes from studies linking alpha-synuclein aggregation to mitochondrial complex III dysfunction. Alpha-synuclein, the protein that forms Lewy bodies in Parkinson's disease, directly inhibits complex III activity and promotes ROS production[@schondorf2022]. This creates a vicious cycle where aggregation impairs function, leading to more oxidative stress and further aggregation. Therapeutic strategies targeting this cycle are currently under investigation.
Tau Pathology and Mitochondrial Dysfunction
New research has established connections between tau pathology and complex III dysfunction. Tau oligomers directly interact with mitochondrial proteins, including complex III subunits, disrupting electron transport and promoting ROS production. The resulting oxidative stress accelerates tau hyperphosphorylation and aggregation, creating another pathogenic feedback loop[@jiang2024].
Therapeutic Targeting Advances
Recent advances in complex III-targeted therapeutics include:
Novel approaches targeting UQCRFS1 specifically include small molecules that protect the iron-sulfur cluster from oxidative damage and gene therapy approaches to deliver functional UQCRFS1 to affected neurons[@iommelli2023].
Molecular Mechanisms
Iron-Sulfur Cluster Assembly
The 2Fe-2S cluster of UQCRFS1 requires specialized assembly machinery for proper insertion and maturation. The ISC (Iron-Sulfur Cluster) assembly system, operating in the mitochondrial matrix, is responsible for cluster biogenesis. Mutations in ISC components can indirectly affect UQCRFS1 function by impairing cluster insertion. This provides a link between general mitochondrial iron metabolism and complex III function.
Quality Control Mechanisms
Mitochondrial quality control mechanisms target damaged complex III:
These mechanisms become less efficient with age, contributing to the age-related onset of neurodegenerative diseases.
Interactions and Pathways
Protein Interactions
Electron Transport Chain
Cross-Linking
Related Genes
- [UQCRB](/genes/uqcrb) — Complex III subunit
- [UQCRQ](/genes/uqcrq) — Complex III subunit
- [CYCS](/genes/cycs) — Cytochrome c
- [CYC1](/genes/cyc1) — Cytochrome c1
Related Mechanisms
- [Electron Transport Chain](/mechanisms/electron-transport-chain)
- [Mitochondrial Complex III](/mechanisms/mitochondrial-complex-iii)
- [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction-neurodegeneration)
- [Oxidative Stress](/mechanisms/oxidative-stress-neurodegeneration)
Disease Pages
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Leigh Syndrome](/diseases/leigh-syndrome)
References
See Also
- [Electron Transport Chain](/mechanisms/electron-transport-chain)
- [Mitochondrial Complex III](/mechanisms/mitochondrial-complex-iii)
- [Mitochondrial Dysfunction](/mechanisms/mitochondrial-dysfunction-neurodegeneration)
- [Oxidative Stress](/mechanisms/oxidative-stress-neurodegeneration)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
Pathway Diagram
The following diagram shows the key molecular relationships involving UQCRFS1 Gene discovered through SciDEX knowledge graph analysis:
▸Metadataorigin_type: v1_polymorphic_backfill
| slug | genes-uqcrfs1 |
| kg_node_id | UQCRFS1 |
| entity_type | gene |
| origin_type | v1_polymorphic_backfill |
| source_table | wiki_pages |
| wiki_page_id | wp-87227b1d1cb5 |
| __merged_from | {'merged_at': '2026-05-13', 'unprefixed_id': 'genes-uqcrfs1'} |
| _schema_version | 1 |
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