LRRK1 - Leucine-Rich Repeat Kinase 1

LRRK1 - Leucine-Rich Repeat Kinase 1

Introduction

Lrrk1 Leucine Rich Repeat Kinase 1 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

LRRK1 (Leucine-Rich Repeat Kinase 1) is a large multi-domain protein kinase related to LRRK2 (Parkin-linked kinase). It is encoded by the LRRK1 gene located on chromosome 15q26.3 and is expressed in various tissues including the brain, with particularly high expression in osteoclasts and [neurons](/entities/neurons). [@xing2006]

LRRK1 - Leucine-Rich Repeat Kinase 1

Introduction

Lrrk1 Leucine Rich Repeat Kinase 1 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

Overview

LRRK1 (Leucine-Rich Repeat Kinase 1) is a large multi-domain protein kinase related to LRRK2 (Parkin-linked kinase). It is encoded by the LRRK1 gene located on chromosome 15q26.3 and is expressed in various tissues including the brain, with particularly high expression in osteoclasts and [neurons](/entities/neurons). [@xing2006]

<div class="infobox infobox-gene"> [@gialluisi2016]
<table> [@boertjes2014]
<tr><th colspan="2" style="background:#f0f0f0;">LRRK1</th></tr> [@yun2015]
<tr><td><strong>Gene Symbol</strong></td><td>LRRK1</td></tr>
<tr><td><strong>Full Name</strong></td><td>Leucine-Rich Repeat Kinase 1</td></tr>
<tr><td><strong>Chromosome</strong></td><td>15q26.3</td></tr>
<tr><td><strong>NCBI Gene ID</strong></td><td>[120892](https://www.ncbi.nlm.nih.gov/gene/120892)</td></tr>
<tr><td><strong>Ensembl ID</strong></td><td>[ENSG00000153902](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000153902)</td></tr>
<tr><td><strong>UniProt ID</strong></td><td>[Q8IWU6](https://www.uniprot.org/uniprot/Q8IWU6)</td></tr>
<tr><td><strong>Protein Length</strong></td><td>2,023 amino acids</td></tr>
<tr><td><strong>Molecular Weight</strong></td><td>~230 kDa</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/parkinson" style="color:#ef9a9a">Parkinson</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">9 edges</a></td>
</tr>
</table>
</div>

Molecular Structure

LRRK1 is a member of the ROCO family of proteins and contains multiple functional domains:

| Domain | Position | Function |
|--------|----------|----------|
| Leucine-Rich Repeats (LRR) | N-terminal | Protein-protein interactions, substrate recognition |
| Ras of Complex (ROC) | Central | GTPase activity, dimerization |
| COR | Central | C-terminal of ROC, regulates GTPase |
| Kinase Domain | C-terminal | Serine/threonine phosphorylation |
| WD40 Repeats | C-terminal | Protein scaffolding, localization |

Normal Function

Kinase Activity

LRRK1 possesses dual enzymatic activities:

• Serine/threonine kinase activity: Autophosphorylation and substrate phosphorylation
• GTPase activity: ROC domain binds and hydrolyzes GTP
• Autophosphorylation: Multiple serine/threonine sites in the activation loop

Cellular Functions

• Lysosomal function: Regulates lysosomal trafficking and autophagy
• Cytoskeletal organization: Modulates actin dynamics and vesicle transport
• Protein quality control: Involved in [ubiquitin-proteasome system](/cell-types/ubiquitin-proteasome-system)
• Synaptic plasticity: Regulates neurotransmitter release

Tissue Distribution

• Bone: Highest expression in osteoclasts (bone-resorbing cells)
• Brain: Moderate expression in [cortex](/brain-regions/cortex), hippocampus, cerebellum
• Heart: Low expression
• Kidney: Moderate expression
• Lung: Low expression

Role in Neurodegeneration

Parkinson's Disease

LRRK1 may play roles in PD pathophysiology:

Interaction with LRRK2

LRRK1 and LRRK2 are related kinases but have distinct functions:

• LRRK2 is a major genetic cause of familial PD
• LRRK1 may modify LRRK2 pathogenicity
• Different brain region expression patterns

Animal Models

| Model | Phenotype | Relevance |
|-------|-----------|-----------|
| LRRK1 knockout mice | Viable, bone abnormalities | Lysosomal dysfunction |
| LRRK1 knockdown | Altered dopamine signaling | PD research |
| LRRK1 kinase-dead | Protein mislocalization | Drug development |

Therapeutic Targeting

| Approach | Mechanism | Development Stage |
|----------|-----------|-------------------|
| Small molecule inhibitors | Block kinase activity | Research |
| GTPase modulators | Regulate ROC domain function | Preclinical |
| ASO therapy | Knockdown expression | Preclinical |
| Gene therapy | Restore functional LRRK1 | Future |

Disease Associations

| Disease | Role | Evidence |
|---------|------|----------|
| Parkinson's Disease | Risk factor, lysosomal function | GWAS, PD models |
| Osteoporosis-parkinsonism syndrome | Bone metabolism | LRRK1 mutations cause bone disease |
| Neurodegeneration | Protein quality control | Cellular models |

Expression in the Brain

LRRK1 is expressed in multiple brain regions:

• Cerebral cortex: Pyramidal neurons in layers 2-6
• [Hippocampus](/brain-regions/hippocampus): CA1-CA3 regions, dentate gyrus
• Basal ganglia: Striatum, substantia nigra pars compacta
• Cerebellum: Purkinje cells, granule cells
• Thalamus: Relay neurons

Key Publications

See Also

• [LRRK2](/proteins/lrrk2-protein)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Alpha-Synuclein](/proteins/snca-protein)
• [Lysosomal Function](/mechanisms/lysosomal-function)mechanisms/lysosomal-dysfunction)
• [PINK1](/proteins/pink1-protein)
• [Parkin](/proteins/parkin-protein)
• [Kinase Inhibitors](/therapeutics/kinase-inhibitors-neurodegeneration)

External Links

• [NCBI Gene: LRRK1](https://www.ncbi.nlm.nih.gov/gene/120892)
• [UniProt: Q8IWU6](https://www.uniprot.org/uniprot/Q8IWU6)
• [GeneCards: LRRK1](https://www.genecards.org/cgi-bin/carddisp.pl?gene=LRRK1)
• [OMIM: LRRK1](https://www.omim.org/entry/607437)

Background

The study of Lrrk1 Leucine Rich Repeat Kinase 1 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.

References

Pathway Diagram

The following diagram shows the key molecular relationships involving LRRK1 - Leucine-Rich Repeat Kinase 1 discovered through SciDEX knowledge graph analysis: