LARS1

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LARS1

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">lars1</th>
</tr>
<tr>
<td class="label">gene = LARS1</td>
<td>name = Leucyl-tRNA Synthetase 1</td>
</tr>
<tr>
<td class="label">ncbi_gene_id = 51520</td>
<td>ensembl = ENSG00000143702</td>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">tRNA-Leu</td>
<td>Substrate</td>
</tr>
<tr>
<td class="label">mTORC1</td>
<td>Signaling</td>
</tr>
<tr>
<td class="label">Rag GTPases</td>
<td>Signal transduction</td>
</tr>
<tr>
<td class="label">Ribosome</td>
<td>Translation</td>
</tr>
<tr>
<td class="label">Aminoacyl-tRNA synthetases</td>
<td>Complex</td>
</tr>
<tr>
<td class="label">Partner</td>
<td>Interaction Type</td>
</tr>
<tr>
<td class="label">tRNA-Leu</td>
<td>Substrate</td>
</tr>
<tr>
<td class="label">mTORC1</td>
<td>Signaling</td>
</tr>
<tr>
<td class="label">Rag GTPases</td>
<td>Signal transduction</td>
</tr>
<tr>
<td class="label">Ribosome</td>
<td>Translation</td>
</tr>
<tr>
<td class="label">Aminoacyl-tRNA synthetases</td>
<td>Complex</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

LARS1

...

LARS1

Overview

LARS1

{{ infobox .infobox-gene
| gene = LARS1
| name = Leucyl-tRNA Synthetase 1
| chromosome = 5q32
| ncbi_gene_id = 51520
| ensembl = ENSG00000143702
| uniprot = Q9P2J5
| gene_family = Aminoacyl-tRNA Synthetases
| diseases = Infantile-Onset Neurodegenerative Disorder, Alzheimer's Disease, Parkinson's Disease
}}

Introduction

LARS1 (Leucyl-tRNA Synthetase 1) encodes leucyl-tRNA synthetase, an essential enzyme in protein synthesis that catalyzes the attachment of L-leucine to its cognate tRNA [1/https://pubmed.ncbi.nlm.nih.gov/12411577/). This enzymatic function is crucial for accurate translation of the genetic code during protein synthesis. Beyond its canonical role in translation, LARS1 has emerged as an important leucine sensor for mTORC1 (mechanistic target of rapamycin complex 1) signaling, linking nutrient availability to cellular growth and metabolism [10/https://pubmed.ncbi.nlm.nih.gov/20679438/).

Pathogenic mutations in LARS1 cause a severe infantile-onset neurodegenerative disorder characterized by progressive cerebellar atrophy, developmental regression, and often premature death [4/https://pubmed.ncbi.nlm.nih.gov/25931480/). This disorder, sometimes called LARS1-associated neurodegeneration, highlights the critical importance of LARS1 function for neuronal survival and development. The dual roles of LARS1 in both protein synthesis and nutrient sensing make it a fascinating player in neurodegeneration research.

Gene and Protein Structure

Genomic Organization

The LARS1 gene is located on chromosome 5q32 and encodes a protein of approximately 1,638 amino acids. The gene contains multiple domains with distinct functional activities.

Protein Architecture

LARS1 contains several functional domains [2](https://pubmed.ncbi.nlm.nih.gov/15221548/):

Aminoacylation domain: Catalyzes leucine attachment to tRNA
tRNA-binding domain: Ensures correct tRNA recognition
Editing domain: Corrects mischarged tRNAs ( proofreading)
C-terminal domain: Involved in leucine sensing and mTORC1 interaction

Function and Mechanism

Aminoacylation Function

LARS1 performs the essential function of attaching leucine to its cognate tRNA [1](https://pubmed.ncbi.nlm.nih.gov/12411577/) [3](https://pubmed.ncbi.nlm.nih.gov/12554948/):

Activation: LARS1 activates leucine using ATP to form leucyl-adenylate

Transfer: The activated leucine is transferred to the 3' end of tRNA-Leu

Proofreading: The editing domain removes mischarged amino acids

Delivery: The charged tRNA is delivered to the ribosome

This process ensures accurate translation of leucine codons (UUA, UUG, CUU, CUG, CUC, CUA) during protein synthesis.

Leucine Sensing

Beyond translation, LARS1 functions as a cellular leucine sensor for mTORC1 activation [10](https://pubmed.ncbi.nlm.nih.gov/20679438/):

Leucine binding to LARS1 induces a conformational change
This change promotes LARS1 interaction with Rag GTPases
Rag GTPases recruit mTORC1 to the lysosome for activation
mTORC1 then regulates cell growth, autophagy, and metabolism

This nutrient-sensing function connects cellular amino acid status to downstream signaling pathways critical for cell survival.

Disease Associations

Infantile-Onset Neurodegenerative Disorder

LARS1 mutations cause a severe autosomal recessive disorder [4](https://pubmed.ncbi.nlm.nih.gov/25931480/) [7](https://pubmed.ncbi.nlm.nih.gov/26494213/):

Clinical Features:

Progressive cerebellar atrophy
Developmental regression
Severe motor impairment
Often premature death in infancy or early childhood
Epileptic seizures in some cases

Mechanism:

Loss of aminoacylation activity
Impaired leucine sensing
Disrupted protein synthesis
mTORC1 dysregulation

Alzheimer's Disease

In [Alzheimer's disease)(/diseases/alzheimer-disease), LARS1 through mTORC1 signaling may contribute [15/https://pubmed.ncbi.nlm.nih.gov/29453462/):

mTORC1 hyperactivation impairs autophagy
Dysregulated protein synthesis affects synaptic function
Leucine sensing may be altered in AD brains

Parkinson's Disease

In [Parkinson's disease](/diseases/parkinsons-disease), LARS1-related pathways are relevant [16/https://pubmed.ncbi.nlm.nih.gov/24791858/):

mTORC1 signaling affects dopaminergic neuron survival
Autophagy impairment contributes to α-synuclein accumulation
Protein synthesis dysregulation affects neuronal function

Role in Neurodegeneration

Protein Synthesis and Neurodegeneration

Proper protein synthesis is essential for neuronal function [11/https://pubmed.ncbi.nlm.nih.gov/20531437/):

Synaptic protein synthesis: Local translation at synapses is critical for plasticity

Axonal transport: Protein synthesis in distal axons supports connectivity

Quality control: Misfolded proteins accumulate when synthesis is impaired

Ribosome stalling: Translation errors can trigger stress responses

mTORC1 Signaling

mTORC1 dysregulation contributes to multiple neurodegenerative processes [17](https://pubmed.ncbi.nlm.nih.gov/20093198/):

Autophagy inhibition: mTORC1 blocks autophagic clearance
Protein synthesis dysregulation: Altered translation of synaptic proteins
Lysosomal function: mTORC1 affects lysosomal degradation
Cellular energetics: Metabolic dysregulation

Ribosome Quality Control

LARS1 editing function is crucial for translation accuracy [14](https://pubmed.ncbi.nlm.nih.gov/18690233/) [15](https://pubmed.ncbi.nlm.nih.gov/19228867/):

Mischarged tRNAs can incorporate wrong amino acids
These errors lead to misfolded proteins
Accumulated misfolded proteins trigger ER stress
Chronic stress leads to neuronal dysfunction

Molecular Pathway: LARS1 in Neurodegeneration

Mermaid diagram (expand to render)

Interaction Network

LARS1 participates in several key molecular networks:

Therapeutic Implications

Targeting mTORC1

Modulating LARS1-mTORC1 signaling may have therapeutic potential [24/https://pubmed.ncbi.nlm.nih.gov/24289475/):

Rapamycin: mTORC1 inhibitor
Leucine restriction: May modulate signaling
Autophagy enhancers: Overcome blockade
Protein synthesis modulators: Restore balance

Gene Therapy

Future approaches may include:

Viral vector delivery of wild-type LARS1
CRISPR-based gene correction
Protein replacement therapy

Summary

LARS1 plays essential roles in both protein synthesis through its aminoacylation function and nutrient sensing through mTORC1 signaling. Pathogenic mutations cause severe infantile neurodegeneration with cerebellar atrophy, while dysregulated LARS1-mTORC1 signaling contributes to common neurodegenerative diseases like Alzheimer's and Parkinson's disease. Understanding LARS1's dual functions provides insights into protein homeostasis, nutrient sensing, and their disruption in neurodegeneration.

External Links

[LARS1 Gene - NCBI](https://www.ncbi.nlm.nih.gov/gene/51520)
[LARS1 Protein - UniProt](https://www.uniprot.org/uniprot/Q9P2J5)
[OMIM: LARS1](https://www.omim.org/entry/151350)
[Ensembl: LARS1](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000143702)

References

[Leucyl-tRNA synthetase: an essential enzyme in protein synthesis (2002)](https://pubmed.ncbi.nlm.nih.gov/12411577/)

[Crystal structure of leucyl-tRNA synthetase (2004)](https://pubmed.ncbi.nlm.nih.gov/15221548/)

[Aminoacyl-tRNA synthetases: role in translation (2003)](https://pubmed.ncbi.nlm.nih.gov/12554948/)

[Leucyl-tRNA synthetase deficiencies cause infantile neurodegeneration (2015)](https://pubmed.ncbi.nlm.nih.gov/25931480/)

[Leucine sensing by LARS1 and mTORC1 activation (2014)](https://pubmed.ncbi.nlm.nih.gov/24129550/)

[Role of aminoacyl-tRNA synthetases in translation (2006)](https://pubmed.ncbi.nlm.nih.gov/16536580/)

[Aminoacyl-tRNA synthetase interactions with ribosome (2007)](https://pubmed.ncbi.nlm.nih.gov/17307808/)

[LARS1 mutations and cerebellar atrophy (2015)](https://pubmed.ncbi.nlm.nih.gov/26494213/)

[Amino acid sensing and mTOR signaling (2012)](https://pubmed.ncbi.nlm.nih.gov/22578493/)

[Leucine as a nutrient signal for mTORC1 (2010)](https://pubmed.ncbi.nlm.nih.gov/20679438/)

[Protein synthesis and neurodegeneration (2010)](https://pubmed.ncbi.nlm.nih.gov/20531437/)

[Leucine deficiency and neuronal dysfunction (2015)](https://pubmed.ncbi.nlm.nih.gov/26494213/)

[tRNA synthetases in protein quality control (2007)](https://pubmed.ncbi.nlm.nih.gov/18690233/)

[Aminoacyl-tRNA synthetase editing domains (2009)](https://pubmed.ncbi.nlm.nih.gov/19228867/)

[mTOR signaling in Alzheimer's disease (2019)](https://pubmed.ncbi.nlm.nih.gov/29453462/)

[mTOR dysfunction in Parkinson's disease (2014)](https://pubmed.ncbi.nlm.nih.gov/24791858/)

[mTOR and autophagy in neurodegeneration (2010)](https://pubmed.ncbi.nlm.nih.gov/20093198/)

[Lysosomal dysfunction in neurodegenerative diseases (2013)](https://pubmed.ncbi.nlm.nih.gov/24140059/)

[Protein synthesis inhibitors in neurodegeneration (2010)](https://pubmed.ncbi.nlm.nih.gov/20363289/)

[Protein homeostasis in aging and neurodegeneration (2011)](https://pubmed.ncbi.nlm.nih.gov/21743440/)

[Ribosome stalling and neurodegeneration (2014)](https://pubmed.ncbi.nlm.nih.gov/24940902/)

[Mitochondrial function in neurodegeneration (2008)](https://pubmed.ncbi.nlm.nih.gov/18157133/)

[ER stress in neurodegenerative diseases (2013)](https://pubmed.ncbi.nlm.nih.gov/23676554/)

[Synaptic protein synthesis and neurodegeneration (2014)](https://pubmed.ncbi.nlm.nih.gov/24732155/)

[Targeting mTOR in neurodegenerative diseases (2013)](https://pubmed.ncbi.nlm.nih.gov/24289475/)

[Amino acid transporters in brain function (2010)](https://pubmed.ncbi.nlm.nih.gov/19843083/)

[Brain amino acid metabolism (2010)](https://pubmed.ncbi.nlm.nih.gov/19191604/)

[Genetic causes of cerebellar atrophy (2016)](https://pubmed.ncbi.nlm.nih.gov/26795569/)

[Epilepsy and neurodegeneration (2015)](https://pubmed.ncbi.nlm.nih.gov/25548161/)

[Developmental neurodegeneration mechanisms (2015)](https://pubmed.ncbi.nlm.nih.gov/26284485/flowchart TD

A["Leucine Availability"] --> B["LARS1 Leucine Binding"]
B --> C{"Function"}
C -->|"Translation"| D["tRNA Charging Protein Synthesis"]
C -->|"Sensing"| E["mTORC1 Activation"]

D --> F["Accurate Translation"]
E --> G["Growth Metabolism"]
E --> H["Autophagy Regulation"]

F --> I["Synaptic Function"]
G --> J["Cellular Homeostasis"]
H --> K["Protein Clearance"]

L["LARS1 Mutation"] --> M["Loss of Function"]
M --> N["Impaired Translation"]
M --> O["mTORC1 Dysregulation"]

N --> P["Misfolded Proteins"]
O --> Q["Autophagy Blockade"]

P --> R["ER Stress"]
Q --> S["Aggregate Accumulation"]
R --> T["Neuronal Dysfunction"]
S --> T
T --> U["Neurodegeneration"]

I --> V["Normal Neuronal Function"]
J --> V
K --> V

style V fill:#0e2e10
style T fill:#3b1114
style U fill:#3b1114

Interaction Network

LARS1 participates in several key molecular networks:

Therapeutic Implications

Targeting mTORC1

Modulating LARS1-mTORC1 signaling may have therapeutic potential [24/https://pubmed.ncbi.nlm.nih.gov/24289475/):

Rapamycin: mTORC1 inhibitor
Leucine restriction: May modulate signaling
Autophagy enhancers: Overcome blockade
Protein synthesis modulators: Restore balance

Gene Therapy

Future approaches may include:

Viral vector delivery of wild-type LARS1
CRISPR-based gene correction
Protein replacement therapy

Summary

External Links

[LARS1 Gene - NCBI](https://www.ncbi.nlm.nih.gov/gene/51520)
[LARS1 Protein - UniProt](https://www.uniprot.org/uniprot/Q9P2J5)
[OMIM: LARS1](https://www.omim.org/entry/151350)
[Ensembl: LARS1](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000143702)