xCT Protein - SLC7A11 Cystine/Glutamate Antiporter

xCT Protein - SLC7A11 Cystine/Glutamate Antiporter

Introduction

Xct Protein Slc7A11 Cystine Glutamate Antiporter is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

xCT Protein - SLC7A11 Cystine/Glutamate Antiporter

Introduction

Xct Protein Slc7A11 Cystine Glutamate Antiporter 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"> [@slcaxct]
<table> [@targeting]
<tr><th colspan="2" style="background:#f0f0f0;">xCT Protein (SLC7A11)</th></tr> [@nrf]
<tr><td><b>Protein Name</b></td><td>xCT (Cystine/Glutamate Antiporter)</td></tr>
<tr><td><b>Gene</b></td><td>[SLC7A11](/genes/slc7a11)</td></tr>
<tr><td><b>UniProt ID</b></td><td>[Q9UPN3](https://www.uniprot.org/uniprot/Q9UPN3)</td></tr>
<tr><td><b>Alternative Names</b></td><td>System Xc− light chain, xCT</td></tr>
<tr><td><b>Molecular Weight</b></td><td>~55 kDa</td></tr>
<tr><td><b>Subcellular Localization</b></td><td>Plasma membrane</td></tr>
<tr><td><b>Protein Family</b></td><td>SLC7 family (heterodimeric amino acid transporters)</td></tr>
<tr><td><b>Structure</b></td><td>12 transmembrane domains</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/aging" style="color:#ef9a9a">Aging</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/amyotrophic-lateral-sclerosis" style="color:#ef9a9a">Amyotrophic Lateral Sclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">883 edges</a></td>
</tr>
</table>
</div>

Overview

xCT (SLC7A11) is the light chain subunit of the cystine/glutamate antiporter system Xc− (system x_c^−). This heterodimeric amino acid transporter plays a crucial role in maintaining cellular redox homeostasis by mediating the uptake of cystine in exchange for glutamate export, thereby providing the essential substrate for glutathione synthesis.

Protein Structure

Transmembrane Architecture

• 12 transmembrane helices forming the transport pore
• N-terminal and C-terminal domains facing the cytoplasm
• Substrate binding pocket in the central region of the transporter

Heterodimer Assembly

xCT (SLC7A11) must partner with 4F2hc (SLC3A2) to form a functional transporter:

• 4F2hc (CD98): Heavy chain providing stabilization
• SLC7A11: Light chain conferring substrate specificity
• Disulfide bond links the two subunits

Normal Function

Amino Acid Transport

The primary function of xCT is to mediate system Xc− activity:

Redox Homeostasis

By providing cysteine for GSH synthesis, xCT:

• Maintains the intracellular GSH pool
• Protects against [reactive oxygen species](/entities/reactive-oxygen-species) (ROS)
• Prevents lipid peroxidation and ferroptosis
• Supports detoxification of xenobiotics

Role in Neurodegeneration

Amyotrophic Lateral Sclerosis (ALS)

• Motor [neurons](/entities/neurons) have high metabolic demands and are vulnerable to oxidative stress
• SLC7A11 expression is dysregulated in ALS
• [Ferroptosis](/entities/ferroptosis) is increasingly recognized as a cell death mechanism in ALS
• Boosting xCT function may protect motor neurons

Parkinson's Disease

• Dopaminergic neurons in substantia nigra face chronic oxidative stress
• GSH levels are depleted in PD brains
• xCT function may be impaired
• Enhancing cystine uptake could support neuronal survival

Alzheimer's Disease

• [Aβ](/proteins/amyloid-beta) plaques and tangles induce oxidative stress
• Astrocytic xCT supports neuronal antioxidant defense
• Age-related decline in xCT function may contribute to AD progression

Therapeutic Targeting

xCT Inhibitors (For Cancer)

| Compound | Mechanism | Clinical Status |
|----------|-----------|-----------------|
| Sulfasalazine | Direct inhibition | Preclinical |
| Erastin | Covalent binding | Research |
| Sorafenib | Multikinase including xCT | FDA approved |
| SAS | Reversible inhibition | Research |

xCT Activators (For Neuroprotection)

| Strategy | Approach | Status |
|----------|----------|--------|
| NRF2 activators | Indirect upregulation | Research |
| Cystine supplementation | Bypass transport | Clinical trials |
| Gene therapy | Increase expression | Preclinical |

Protein Interactions

| Partner | Interaction Type | Function |
|---------|-----------------|----------|
| SLC3A2 (4F2hc) | Complex formation | Functional transporter |
| NRF2 | Transcriptional regulation | Stress-responsive activation |
| KEAP1 | Regulation | NRF2-Keap1 pathway |
| GCLM | Co-regulation | GSH synthesis gene cluster |

Key Publications

Background

The study of Xct Protein Slc7A11 Cystine Glutamate Antiporter 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.

Pathway & Interaction Diagram

Interactive diagram showing SLC7A11 key relationships in the SciDEX knowledge graph (15 connections shown).

See Also

• [SLC7A11 Gene](/genes/slc7a11)
• [GPX4 Protein](/proteins/gpx4-protein)
• [Ferroptosis Pathway](/entities/ferroptosis)
• [Oxidative Stress Pathway](/mechanisms/oxidative-stress)
• [Glutathione Metabolism](/mechanisms/glutathione-metabolism)
• [ALS Proteins](/content/proteins)

External Links

• [UniProt: Q9UPN3](https://www.uniprot.org/uniprot/Q9UPN3)
• [PDB: 6GES (structure)](https://www.ebi.ac.uk/pdbe/entry/pdb/6ges)
• [AlphaFold Model](https://alphafold.ebi.ac.uk/entry/Q9UPN3)
• [GeneCards: SLC7A11](https://www.genecards.org/cgi-bin/carddisp.pl?gene=SLC7A11)

References