TLR5 Protein

TLR5 Protein - Toll-Like Receptor 5

Introduction

Tlr5 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"> [@akira2004]
<table> [@sampson2016]
<tr><th colspan="2" style="background:#f0f0f0;">Protein Information</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Toll-Like Receptor 5 (TLR5)</td></tr>
<tr><td><strong>Gene</strong></td><td>TLR5</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>Q9R279</td></tr>
<tr><td><strong>PDB Structure</strong></td><td>5GS0, 3J0N</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>~97 kDa</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Cell membrane, Endosomes</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Toll-Like Receptor Family</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">7 edges</a></td>
</tr>
</table>
</div>

Overview

TLR5 (Toll-Like Receptor 5) is a pattern recognition receptor of the innate immune system that recognizes bacterial flagellin. TLR5 is expressed on immune cells and various tissues, where it triggers pro-inflammatory responses upon flagellin recognition. Emerging research suggests TLR5 plays roles in neuroinflammation and neurodegenerative diseases.

Structure

TLR5 is a type I transmembrane protein:

...

TLR5 Protein - Toll-Like Receptor 5

Introduction

Tlr5 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"> [@akira2004]
<table> [@sampson2016]
<tr><th colspan="2" style="background:#f0f0f0;">Protein Information</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Toll-Like Receptor 5 (TLR5)</td></tr>
<tr><td><strong>Gene</strong></td><td>TLR5</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>Q9R279</td></tr>
<tr><td><strong>PDB Structure</strong></td><td>5GS0, 3J0N</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>~97 kDa</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Cell membrane, Endosomes</td></tr>
<tr><td><strong>Protein Family</strong></td><td>Toll-Like Receptor Family</td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">7 edges</a></td>
</tr>
</table>
</div>

Overview

TLR5 (Toll-Like Receptor 5) is a pattern recognition receptor of the innate immune system that recognizes bacterial flagellin. TLR5 is expressed on immune cells and various tissues, where it triggers pro-inflammatory responses upon flagellin recognition. Emerging research suggests TLR5 plays roles in neuroinflammation and neurodegenerative diseases.

Structure

TLR5 is a type I transmembrane protein:

Domain Architecture

• Signal peptide: N-terminal signal peptide
• Leucine-rich repeats (LRRs): 20 LRR motifs in extracellular domain for flagellin recognition
• LRR C-terminal flanking region: Important for ligand binding
• Transmembrane domain: Single pass alpha-helical transmembrane region
• TIR domain: Toll/IL-1 receptor signaling domain

Structure-Function

• Flagellin recognition occurs through LRR motifs
• TIR domain initiates downstream signaling via MyD88 adaptor

Normal Function

TLR5 plays important roles in innate immunity:

Immune Recognition

• Flagellin detection: Specifically recognizes bacterial flagellin
• Pattern recognition: Part of innate immune surveillance
• DAMP recognition: May recognize some endogenous ligands

Signaling Pathways

MyD88-dependent pathway: Rapid [NF-kB](/entities/nf-kb) and MAPK activation

Pro-inflammatory cytokines: TNF-alpha, IL-1beta, IL-6

Immune cell activation: Activates neutrophils, macrophages

Cellular Functions

• Phagocytosis: Enhances bacterial clearance
• Cytokine production: Induces inflammatory mediators
• Adaptive immunity: Bridges innate and adaptive immune responses

Role in Disease

Alzheimer Disease

• TLR5 may influence AD through recognition of bacterial products
• Gut microbiome-derived flagellin can activate TLR5
• Modulates neuroinflammation through microglial activation

Parkinson Disease

• TLR5 signaling in PD pathogenesis
• [Gut-brain axis](/entities/gut-brain-axis) involvement via bacterial flagellin
• May contribute to microglial activation in substantia nigra

Neuroinflammation

• TLR5 on [microglia](/cell-types/microglia-neuroinflammation) can initiate inflammatory responses
• Potential therapeutic target for neuroinflammatory conditions

Expression

| Cell Type | Expression Level | Notes |
|----------|-----------------|-------|
| Monocytes | High | Primary peripheral expression |
| Macrophages | High | Phagocytic cells |
| Neutrophils | High | First responders |
| Dendritic Cells | Moderate | Antigen presentation |
| Microglia | Moderate | Brain immune cells |
| Intestinal Epithelium | High | Barrier function |

Therapeutic Targeting

| Approach | Agent | Status | Notes |
|----------|-------|--------|-------|
| TLR5 Antagonists | Flagellin peptides | Research | Block flagellin binding |
| Anti-inflammatory | Natural compounds | Preclinical | Modulate signaling |
| [Microbiome](/entities/microbiome) Modulation | Diet/Probiotics | Investigational | Reduce flagellin exposure |

Protein Interactions

• MyD88: Primary adaptor protein
• [TLR4](/entities/tlr4): Can form heterodimers in some contexts
• TIRAP: Adaptor protein
• Mal: Signaling adaptor

Background

The study of Tlr5 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

• TLR5 Gene
• [Toll-Like Receptors](/mechanisms/toll-like-receptor-signaling)
• [Neuroinflammation](/mechanisms/neuroinflammation-pathway)
• [Microglia](/cell-types/microglia)
• [Innate Immunity](/mechanisms/neuroinflammation)
• [Gut-Brain Axis](/mechanisms/gut-brain-axis)

External Links

• [UniProt: TLR5](https://www.uniprot.org/uniprot/Q9R279)
• [PDB: TLR5](https://www.ebi.ac.uk/pdbe/pdbe-search?targetUrl=http://www.ebi.ac.uk/pdbe/entry/pdb/5gs0)
• [NCBI Protein: TLR5](https://www.ncbi.nlm.nih.gov/protein/7099)

References

Hayashi F, Smith KD, Ozinsky A, et al, The innate immune response to bacterial flagellin is mediated by Toll-like receptor 5 (2001)

Akira S, Takeda K, Toll-like receptor signalling (2004)

Sampson TR, Debelius JW, Thron T, et al, Gut microbiota regulate motor deficits and neuroinflammation in a model of Parkinson disease (2016)