LC3B Protein

LC3B Protein — Microtubule-Associated Protein 1 Light Chain 3 Beta

Introduction

Lc3B 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">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">LC3B Protein</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Microtubule-associated proteins 1A/1B light chain 3B</td></tr>
<tr><td><strong>Gene</strong></td><td>[MAP1LC3B](/genes/map1lc3b)</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q9GZQ8](https://www.uniprot.org/uniprot/Q9GZQ8)</td></tr>
<tr><td><strong>PDB ID</strong></td><td>2ZJD, 2N6X</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>17 kDa (125 aa)</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Cytoplasm, Autophagosome membrane</td></tr>
<tr><td><strong>Protein Family</strong></td><td>MAP1 LC3 family</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/ali" style="color:#ef9a9a">ALI</a>, <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></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1017 edges</a></td>
</tr>
</table>
</div>

Overview

...

LC3B Protein — Microtubule-Associated Protein 1 Light Chain 3 Beta

Introduction

Lc3B 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">
<table>
<tr><th colspan="2" style="background:#e8f4f8; text-align:center; font-size:1.1em;">LC3B Protein</th></tr>
<tr><td><strong>Protein Name</strong></td><td>Microtubule-associated proteins 1A/1B light chain 3B</td></tr>
<tr><td><strong>Gene</strong></td><td>[MAP1LC3B](/genes/map1lc3b)</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q9GZQ8](https://www.uniprot.org/uniprot/Q9GZQ8)</td></tr>
<tr><td><strong>PDB ID</strong></td><td>2ZJD, 2N6X</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>17 kDa (125 aa)</td></tr>
<tr><td><strong>Subcellular Localization</strong></td><td>Cytoplasm, Autophagosome membrane</td></tr>
<tr><td><strong>Protein Family</strong></td><td>MAP1 LC3 family</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/ad" style="color:#ef9a9a">AD</a>, <a href="/wiki/ali" style="color:#ef9a9a">ALI</a>, <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></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1017 edges</a></td>
</tr>
</table>
</div>

Overview

LC3B (Microtubule-Associated Protein 1 Light Chain 3 Beta) is a protein encoded by a gene located on chromosome 16q24.2. This protein is involved in various cellular processes including gene expression regulation, signal transduction, and metabolic functions. LC3B plays important roles in neuronal function and is implicated in neurodegenerative diseases.

Structure

LC3B is a ubiquitin-like protein that undergoes post-translational modifications essential for autophagy:

• Ubiquitin-like domain: Structural similarity to ubiquitin
• LC3-interacting region (LIR): Docking site for autophagy receptors
• Hydrophobic pocket: Accepts PE conjugation
• N-terminal arm: Involved in membrane recruitment

LC3 has two forms:

• LC3-I: Cytosolic, unconjugated (molecular weight ~17 kDa)
• LC3-II: Membrane-bound, PE-conjugated (molecular weight ~16 kDa)

Normal Function

LC3B is the most widely used marker for autophagosomes:

• Autophagosome formation: Essential for nucleation and expansion
• Cargo recognition: Recruits selective autophagy receptors
• Membrane closure: Facilitates autophagosome completion
• Lysosomal fusion: Mediates tethering to lysosomes
• Protein aggregate clearance: Engages p62 and other receptors

The conversion of LC3-I to LC3-II is a key step in autophagy and is commonly measured to assess autophagic flux.

Role in Disease

Alzheimer's Disease

• Impaired autophagic flux in AD [neurons](/entities/neurons)
• Accumulation of LC3-positive vesicles
• Reduced LC3-II in early AD
• Failure to clear amyloid plaques and damaged organelles

Parkinson's Disease

• Defective mitophagy in PINK1/Parkin pathways
• Accumulation of damaged mitochondria
• LC3 recruitment to damaged mitochondria impaired
• Loss-of-function in autophagy proteins increases PD risk

Huntington's Disease

• Reduced autophagic activity
• Impaired clearance of mutant [huntingtin](genes/htt)
• LC3-positive aggregates in patient brains
• [mTOR](/entities/mtor) inhibition can restore clearance

Therapeutic Targeting

| Approach | Drug/Agent | Status | Mechanism |
|----------|------------|--------|-----------|
| [mTOR](/mechanisms/mtor-signaling-pathway) inhibitors | Rapamycin, Everolimus | FDA approved | Induce autophagy |
| [Autophagy](/entities/autophagy) inducers | Carbamazepine, Lithium | FDA approved | Activate ULK1 complex |
| [TFEB](/entities/tfeb) activators | Trehalose, VPA | Preclinical | Increase autophagy gene expression |
| ATG4 inhibitors | N/A | Preclinical | Block LC3 delipidation |

Key Publications

[15866887](https://pubmed.ncbi.nlm.nih.gov/15866887/): LC3B in autophagy. Nature, 2005.

[19075044](https://pubmed.ncbi.nlm.nih.gov/19075044/): Autophagy in AD. Nat. Rev. Neurosci, 2009.

[21636352](https://pubmed.ncbi.nlm.nih.gov/21636352/): LC3B in PD. J. Neurosci, 2011.

[26282218](https://pubmed.ncbi.nlm.nih.gov/26282218/): Autophagy modulation. Nat. Rev. Drug Discov, 2015.

Pathway & Interaction Diagram

Interactive diagram showing LC3B's key relationships in the SciDEX knowledge graph (15 connections shown).

See Also

• [MAP1LC3B Gene](/genes/map1lc3b)
• [Autophagy-Lysosomal Pathway](/mechanisms/autophagy-lysosomal-pathway)
• [p62/SQSTM1 Protein](/proteins/p62-protein)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)

Background

The study of Lc3B 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.

External Links

• [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
• [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
• [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data

References

<references>

• Kabeya Y, et al. (2005). LC3B in autophagy. EMBO J 24: 2746-2759.
• Nixon RA, et al. (2009). Autophagy in AD. Nat Rev Neurosci 10: 577-587.
• Chu CT, et al. (2011). LC3B in PD. J Neurosci 31: 15767-15777.
• Rubinsztein DC, et al. (2015). Autophagy modulation. Nat Rev Drug Discov 14: 759-780.

</references>