COX5A Protein

Cytochrome C Oxidase Subunit 5A (COX5A)

Introduction

Cox5A Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-protein"> [@gandhi2012]
<table> [@stryber2021]
<tr><th colspan="2" style="background:#1a5f7a;color:white;">COX5A — Cytochrome C Oxidase Subunit 5A</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Cytochrome C Oxidase Subunit 5A</td></tr>
<tr><td><strong>Gene</strong></td><td>[COX5A](/genes/cox5a)</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[P20674](https://www.uniprot.org/uniprot/P20674)</td></tr>
<tr><td><strong>PDB ID</strong></td><td>1V54, 2EIJ</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>~16 kDa</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Inner mitochondrial membrane</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Cytochrome c oxidase subunit Va family</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/carcinoma" style="color:#ef9a9a">Carcinoma</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">9 edges</a></td>
</tr>
</table>
</div>

Overview

...

Cytochrome C Oxidase Subunit 5A (COX5A)

Introduction

Cox5A Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-protein"> [@gandhi2012]
<table> [@stryber2021]
<tr><th colspan="2" style="background:#1a5f7a;color:white;">COX5A — Cytochrome C Oxidase Subunit 5A</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Cytochrome C Oxidase Subunit 5A</td></tr>
<tr><td><strong>Gene</strong></td><td>[COX5A](/genes/cox5a)</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[P20674](https://www.uniprot.org/uniprot/P20674)</td></tr>
<tr><td><strong>PDB ID</strong></td><td>1V54, 2EIJ</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>~16 kDa</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Inner mitochondrial membrane</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Cytochrome c oxidase subunit Va family</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/carcinoma" style="color:#ef9a9a">Carcinoma</a>, <a href="/wiki/ms" style="color:#ef9a9a">Ms</a>, <a href="/wiki/tumor" style="color:#ef9a9a">Tumor</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">9 edges</a></td>
</tr>
</table>
</div>

Overview

COX5A is the 5A subunit of cytochrome c oxidase (complex IV) of the mitochondrial electron transport chain. This protein is nuclear-encoded and imported into mitochondria where it assembles into the mature complex.

Cytochrome c oxidase (COX) is a multimeric complex consisting of:

• 13 mitochondrial-encoded subunits
• 10 nuclear-encoded subunits (in mammals)

COX5A is one of the nuclear-encoded subunits critical for proper complex assembly and function.

Structure

COX5A structure features:

• Transmembrane helix — anchors protein in inner mitochondrial membrane
• Water-soluble domain — extends into the mitochondrial matrix
• Binding sites — for cytochrome c interaction

The protein contains:

• ~150 amino acids
• Molecular weight of ~16 kDa
• Single transmembrane domain

Normal Function

Electron Transport

• Cytochrome c oxidation — receives electrons from cytochrome c
• Oxygen reduction — catalyzes the final step of the ETC: 4 Cyt c (reduced) + 8 H+ + O2 → 4 Cyt c (oxidized) + 4 H2O
• Proton pumping — contributes to the electrochemical gradient

Mitochondrial Respiration

• Essential for aerobic ATP production
• Regulates [reactive oxygen species](/entities/reactive-oxygen-species) (ROS) production
• Maintains mitochondrial membrane potential

Role in Disease

Alzheimer's Disease

• Reduced COX activity in AD brain and platelets
• Contributes to neuronal energy failure
• Impaired oxidative phosphorylation leads to synaptic dysfunction
• Correlates with cognitive decline severity

Parkinson's Disease

• Complex IV deficiency in substantia nigra pars compacta
• Contributes to dopaminergic neuron vulnerability
• Energy deficit exacerbates [α-synuclein](/proteins/alpha-synuclein) toxicity

Leigh Syndrome

• Mutations in COX subunits can cause classic Leigh syndrome
• Characterized by:
• Progressive neurodegeneration
• Basal ganglia lesions
• Lactic acidosis
• Early childhood onset

Therapeutic Targeting

Current Approaches

• CoQ10 supplementation — supports electron flow
• Mitochondrial nutrients — L-carnitine, alpha-lipoic acid
• Exercise — stimulates mitochondrial biogenesis

Experimental Approaches

• Gene therapy — deliver COX genes
• Mitochondrial transplantation
• Small molecules to enhance complex IV assembly

Background

The study of Cox5A Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

See Also

• [COX5A Gene](/genes/cox5a)
• [Mitochondrial Electron Transport Chain](/mechanisms/mitochondrial-electron-transport-chain)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Mitochondrial Dynamics](/entities/mitochondrial-dynamics)

External Links

• [UniProt - COX5A](https://www.uniprot.org/uniprot/P20674)
• [PDB - COX5A](https://www.rcsb.org/structure/1V54)
• [NCBI Protein - COX5A](https://www.ncbi.nlm.nih.gov/protein/NP_001277.1)

References

[Parikh et al., Mitochondrial dysfunction in Alzheimer's disease (2009) (2009)](https://doi.org/10.1016/j.neurobiolaging.2007.12.023)

[Gandhi et al., COX deficiency in neurodegeneration (2012) (2012)](https://doi.org/10.1016/j.tibs.2012.06.008)

[Stryber et al., Cytochrome c oxidase in AD brain (2021) (2021)](https://doi.org/10.1007/s12035-021-02345-5)