| Gene Symbol | LRRK2 |
|---|
| Full Name | Leucine-Rich Repeat Kinase 2 (Leucine-Rich Repeat Pseudokinase) |
|---|
| Chromosomal Location | 12q12 |
|---|
| NCBI Gene ID | 120892 |
|---|
| OMIM | 609460 |
|---|
| Ensembl ID | ENSG00000100906 |
|---|
| UniProt ID | Q5MWN9 |
|---|
| Associated Diseases | Parkinson's Disease (most common genetic cause) |
|---|
LRRK2 (Leucine-Rich Repeat Kinase 2), also known as LREK (a common misnaming), is one of the largest known protein kinases (2527 amino acids) and represents the most common genetic cause of familial Parkinson's disease (PD), accounting for 5-10% of autosomal dominant PD cases. The protein contains multiple functional domains including ROC (Ras of complex proteins) GTPase domain, COR (C-terminal of ROC) domain, and kinase domain, making it a unique signaling hub that integrates multiple cellular processes. Pathogenic LRRK2 mutations lead to enhanced kinase activity and subsequent neurotoxicity through mechanisms affecting autophagy, mitochondrial function, protein homeostasis, and synaptic transmission.
¶ Domain Architecture
LRRK2 is a complex multi-domain protein:
[N-terminus] → LRR → LRR → ROC → COR → Kinase → WD40 [C-terminus]
¶ Domain Functions
- Leucine-Rich Repeats (LRR): Protein-protein interactions, localization
- ROC Domain: GTP binding and hydrolysis (mutated in PD)
- COR Domain: Dimerization and regulation
- Kinase Domain: Autophosphorylation and substrate phosphorylation (enhanced in PD)
- WD40 Repeat: Scaffold for protein complexes
| Mutation |
Domain |
Effect |
| G2019S |
Kinase |
Enhanced autophosphorylation |
| R1441C/G/H |
ROC |
GTPase dysfunction |
| N1437H |
ROC |
GTPase dysfunction |
| Y1699C |
COR |
Dimerization defect |
| I2020T |
Kinase |
Substrate recognition |
- Prevalence: 3-5% of PD cases (higher in some populations)
- Penetrance: Age-dependent (~30% by age 80)
- Effect: Increased kinase activity
- Origin: Founder effects in multiple populations
Pathogenic mutations increase LRRK2 autophosphorylation and kinase activity toward substrates:
- Leads to altered neuronal signaling
- Generates toxic species
- Affects protein homeostasis
LRRK2 mutations disrupt:
- Mitochondrial dynamics (fusion/fission)
- Mitophagy and quality control
- Energy metabolism
- ROS handling
- LRRK2 regulates autophagy at multiple stages
- Pathogenic mutations impair autophagic flux
- Leads to protein aggregation
- Alters neurotransmitter release
- Affects dopaminergic transmission
- Contributes to neurodegeneration
┌─────────────────┐
│ LRRK2 │
│ (inactive) │
└────────┬────────┘
│
GTP
│
┌────────▼────────┐
│ LRRK2(active)│
└────────┬────────┘
│
┌───────────────┼───────────────┐
│ │ │
┌────▼────┐ ┌───▼───┐ ┌────▼────┐
│Autophos │ │Transl │ │Mitoch │
│(substr) │ │Modif │ │Func │
└─────────┘ └───────┘ └─────────┘
Multiple LRRK2 kinase inhibitors in development:
- DNL151: Phase I/II trials
- BIIB122: Clinical trials
- LL34: Preclinical
- Allosteric inhibitors
- ROC domain modulators
LRRK2 is the most common genetic cause:
- 5-10% of familial PD
- 1-3% of simplex PD
- Age-dependent penetrance
Clinical features of LRRK2-PD:
- Typical idiopathic PD phenotype
- Often indistinguishable from sporadic PD
- May have earlier onset
- Substantia nigra pars compacta (dopaminergic neurons)
- Cortex
- Hippocampus
- Cerebellum
- Striatum
- Cytoplasmic
- Membrane-associated
- Vesicular
- Rab proteins: Key substrates
- 14-3-3 proteins: Regulation
- BAG5: Mitochondrial regulation
- Filamin: Cytoskeletal interactions
- MAPK/ERK pathway
- mTOR pathway
- Autophagy pathway
- LRRK2 G2019S knock-in mice
- Overexpression models
- Conditional knockouts
- Motor dysfunction
- Neuropathology
- Mitochondrial defects
LRRK2 is the most common genetic cause of familial Parkinson's disease, encoding a large kinase with multiple functional domains. Pathogenic mutations, especially G2019S, lead to enhanced kinase activity and neurotoxicity through mechanisms involving autophagy impairment, mitochondrial dysfunction, and altered synaptic transmission. Therapeutic targeting of LRRK2 is an active area of drug development with multiple clinical candidates.
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