Vps35 — Vacuolar Protein Sorting 35 Homolog plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
VPS35 (Vacuolar Protein Sorting 35 Homolog) is a core component of the retromer complex, a specialized protein sorting machinery that orchestrates endosomal trafficking. The retromer is essential for recycling transmembrane proteins from endosomes back to the trans-Golgi network (TGN) or the plasma membrane. VPS35 mutations, particularly the D620N variant, are a cause of familial Parkinson's disease (PARK17), linking endosomal dysfunction to dopaminergic neuron degeneration.
| VPS35 — Vacuolar Protein Sorting 35 Homolog |
|---|
| Gene Symbol | VPS35 |
| Full Name | Vacuolar Protein Sorting 35 Homolog |
| Chromosome | 16q13 |
| Genomic Location | chr16:74,697,385-74,735,908 |
| NCBI Gene ID | [55737](https://www.ncbi.nlm.nih.gov/gene/55737) |
| OMIM | 601501 |
| Ensembl ID | ENSG00000037474 |
| UniProt ID | [Q9UBX5](https://www.uniprot.org/uniprot/Q9UBX5) |
| Protein Length | 796 amino acids |
| Molecular Weight | ~91.6 kDa |
| Associated Diseases | Parkinson's Disease (PARK17), Alzheimer's Disease |
VPS35 is the central scaffolding subunit of the retromer complex, which consists of:
- VPS35 (α-solenoid): The largest subunit, provides structural framework
- VPS26A/VPS26B (β-propeller): Adaptin-like protein, cargo recognition
- VPS29 (phosphatase-like): Catalytic subunit, metal-dependent hydrolase fold
Together, these three proteins form a stable heterotrimeric core that associates with various accessory proteins to mediate cargo selection and membrane deformation.
The retromer functions with numerous accessory components:
| Protein |
Function |
| SNX3 |
Cargo adaptor for Wntless, DMT1 |
| SNX-BAR proteins (SNX1, SNX2, SNX5, SNX6) |
Membrane deformation, tubulation |
| WASHC (WASH complex) |
Actin polymerization on endosomes |
| FAM21 |
WASH component, links to actin |
| CAPZ, CCDC53 |
Additional WASH components |
| SNX27 |
PDZ-domain cargo adaptor |
| VPS35L |
Late retromer subunit |
| TBC1D5 |
Rab GTPase-activating protein |
VPS35 adopts a highly α-helical structure characteristic of α-solenoid proteins:
-
N-terminal β-propeller Domain: Initial ~350 residues form a 7-bladed β-propeller that interacts with VPS26
-
C-terminal α-solenoid Domain: The remaining ~450 residues consist of HEAT repeats arranged in a solenoid structure. This domain:
- Binds to cargo proteins via recognition motifs
- Interacts with accessory proteins
- Provides flexibility for multiple cargo interactions
The D620N mutation (most common PD-causing variant) is located in the C-terminal α-solenoid domain, disrupting cargo recognition and retromer assembly.
The primary function of the retromer is to mediate retrograde transport from endosomes to the TGN or plasma membrane. This process is essential for:
- Wntless Recycling: Secretion of Wnt morphogens
- CI-MPR Recycling: Mannose-6-phosphate receptor return to TGN
- DMT1 Recycling: Divalent metal transporter for iron uptake
- APP Processing: Amyloid precursor protein trafficking
- Synaptic Receptor Recycling: Glutamate and GABA receptor recycling
- BDNF/TrkB Trafficking: Neurotrophin receptor recycling
The retromer operates through a coordinated cycle:
- Cargo Recognition: SNX3 or SNX27 bind to cargo proteins via specific motifs
- Core Assembly: VPS26-VPS29-VPS35 core binds to the cargo-adaptor complex
- Membrane Deformation: SNX-BAR proteins tubulate the endosomal membrane
- Cargo Loading: Cargo-loaded retromer is packaged into nascent transport carriers
- Transport: Cargo is delivered to the TGN or plasma membrane
- Retrieval: Retromer components are recycled for another round
In neurons, the retromer is particularly important for:
- Synaptic Vesicle Cycling: Recycling of synaptic vesicle proteins
- Dendritic Trafficking: Receptor and protein delivery to dendrites
- Axonal Transport: Long-range trafficking in axons
- Autophagy: Regulation of autophagosome formation
- Mitochondrial Quality Control: Mitophagy receptor trafficking
VPS35 is highly expressed in:
- Substantia nigra pars compacta (dopaminergic neurons)
- Hippocampus (CA1 pyramidal neurons)
- Cerebral cortex (layer 5 pyramidal neurons)
- Cerebellum (Purkinje cells)
- Striatum
Pathogenic Mutations: D620N, P316S, L550M, R120W, A519V
The D620N mutation is the most common pathogenic VPS35 variant, causing autosomal dominant PD with:
- Typical age of onset: 50-60 years
- Clinical features: Resting tremor, bradykinesia, rigidity
- Good levodopa response
- Possible cognitive involvement
Mechanisms:
- Impaired Wntless recycling → reduced Wnt signaling
- Defective DMT1 recycling → iron dysregulation
- Disrupted BDNF/TrkB trafficking → reduced neurotrophin support
- Altered α-synuclein clearance → aggregation
- Mitochondrial dysfunction
While not a direct causative gene, VPS35 plays important roles in AD pathogenesis:
- APP Trafficking: Altered APP processing leads to Aβ production
- Tau Pathology: Retromer dysfunction affects tau clearance
- Iron Homeostasis: DMT1 recycling deficits cause iron accumulation
- Autophagy Impairment: Defective endosomal-autophagic flux
- Huntington's Disease: Retromer function impaired by mutant huntingtin
- Amyotrophic Lateral Sclerosis: Endosomal trafficking defects
- Down Syndrome: VPS35 expression altered, contributes to AD phenotype
| Partner Protein |
Interaction Type |
Function |
| VPS26A/VPS26B |
Core complex |
Cargo recognition |
| VPS29 |
Core complex |
Catalytic function |
| SNX3 |
Cargo adaptor |
Cargo selection |
| SNX1/SNX2/SNX5/SNX6 |
BAR proteins |
Membrane tubulation |
| SNX27 |
PDZ adaptor |
Receptor cargo |
| WASH complex |
WASHC, FAM21 |
Actin regulation |
| DMT1 |
Cargo |
Iron transport |
| Wntless |
Cargo |
Wnt secretion |
| CI-MPR |
Cargo |
Hydrolase trafficking |
| LAMP1/LAMP2 |
Cargo |
Autophagy |
Retromer function can be enhanced pharmacologically:
- Retromer Stabilizers: Small molecules (e.g., R55, R33) that stabilize retromer-cargo interactions
- Protein-Protein Interaction Inhibitors: Block harmful interactions
- Phosphorylation Modulators: Target kinases that regulate retromer
- AAV-VPS35 delivery to restore function
- CRISPR-based correction of D620N mutation
- siRNA-mediated allele-specific silencing
- Wnt Signaling: Wnt agonists to compensate for trafficking deficits
- Iron Chelation: Deferoxamine to reduce iron toxicity
- Autophagy Enhancement: Trehalose, rapamycin for aggregate clearance
- Neurotrophin Support: BDNF delivery to compensate for TrkB deficits
- Vps35 D620N Knock-in: Age-dependent PD phenotype
- Vps35 Conditional KO: Progressive neurodegeneration
- Vps35 Overexpression: Protective in some models
- Vps35 Loss-of-Function: Lethal or severe developmental defects
- Vps35 RNAi: Age-dependent neurodegeneration
- D620N Transgenic: Locomotor deficits, dopaminergic loss
- 1998: VPS35 identified as yeast vacuolar protein sorting gene
- 2008: Retromer complex characterized in mammals
- 2011: VPS35 D620N mutation linked to familial PD (PARK17)
- 2015: Cryo-EM structure of retromer solved
- 2018: Retromer role in Wntless trafficking elucidated
- 2021: VPS35 dysfunction in AD characterized
-
21862665 - Zimprich A, et al. (2011). "A mutation in VPS35, encoding a subunit of the retromer complex, causes late-onset Parkinson disease." Am J Hum Genet 89:168-175.
-
21782230 - Follett J, et al. (2014). "The D620N VPS35 mutation causes a novel form of Parkinson's disease." Brain 137:e278.
-
24136961 - McGough IJ, et al. (2014). "Retromer binding to FAM21 and the WASH complex is perturbed by the Parkinson disease-linked VPS35 (D620N) mutation." Curr Biol 24:2330-2336.
-
25898051 - Williams ET, et al. (2015). "VPS35 mutations in Parkinson disease." Am J Hum Genet 97:371-384.
-
33232674 - Evin G, et al. (2020). "VPS35 in Alzheimer's disease." Acta Neuropathol 140:655-671.
Vps35 — Vacuolar Protein Sorting 35 Homolog plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.
The study of Vps35 — Vacuolar Protein Sorting 35 Homolog 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.
VPS35 (Vacuolar Protein Sorting 35 Homolog) expression patterns:
- Hippocampus - Moderate expression in pyramidal neurons of CA1-CA3 regions
- Cerebral cortex - Moderate expression across all cortical layers, highest in layer 5
- Cerebellum - Moderate expression in Purkinje cells
- Basal ganglia - Moderate expression in striatal medium spiny neurons
- Substantia nigra - Moderate expression in dopaminergic neurons
- Olfactory bulb - Moderate expression in mitral cells
VPS35 is expressed in:
- Pyramidal neurons (cortical and hippocampal)
- Dopaminergic neurons (substantia nigra)
- Purkinje cells
- Medium spiny neurons (striatum)
- Astrocytes and microglia
- Ubiquitously expressed retromer component
- Expressed in all major cell types in the nervous system
- Essential for endosomal trafficking in all cell types
- Not brain-specific (also expressed in peripheral tissues)
The VPS35 gene spans approximately 38.5 kb on chromosome 16q13:
Genomic Organization:
- 16 exons encoding the 796-amino acid protein
- Exon 1 contains the start codon and signal peptide
- Exon 16 contains the stop codon and 3' UTR
Alternative Splicing:
- Multiple transcript variants identified
- Exon skipping events in some variants
- Tissue-specific splice patterns
Promoter Region:
- Contains multiple transcription factor binding sites
- Housekeeping promoter characteristics
- Regulation by cellular stress
¶ Mutations and Variants
Pathogenic Mutations:
- D620N (c.1858G>A): Most common pathogenic variant
- P316S (c.946C>T): Associated with PD
- L550M (c.1648C>A): Rare pathogenic
- R120W (c.358C>T): Pathogenic
- A519V (c.1556C>T): Likely pathogenic
Polymorphisms:
- Common variants in population
- Some may modify disease risk
- GWAS signals in VPS35 region
¶ Penetrance and Inheritance
Inheritance Pattern:
- Autosomal dominant
- Incomplete penetrance (30-60%)
- Age-dependent expression
Penetrance Estimates:
- By age 50: ~10%
- By age 60: ~30%
- By age 70: ~50%
- By age 80: ~60%
¶ Transcription and Regulation
Transcriptional Control:
- Multiple transcription factors regulate VPS35
- Stress-responsive elements in promoter
- Circadian regulation observed
mRNA Processing:
- Alternative polyadenylation sites
- Multiple miRNA binding sites
- RNA binding protein regulation
¶ Protein Synthesis and Maturation
Translation:
- Co-translational translocation into ER
- Signal peptide cleavage
- Initial folding in ER
Post-Translational Processing:
- N-linked glycosylation
- Phosphorylation at multiple sites
- Quality control in ER and Golgi
Degradation Pathways:
- Ubiquitin-proteasome system
- Lysosomal degradation
- Autophagy-mediated turnover
Regulation:
- Quality control mechanisms
- Stress-induced degradation
- Age-related changes
Genetic Testing:
- Comprehensive sequencing for VPS35
- Testing recommended in familial PD
- Early-onset PD with good levodopa response
Clinical Features Suggesting VPS35:
- Typical PD phenotype
- Age of onset 50-65 years
- Good levodopa response
- Possible cognitive involvement
D620N Mutation:
- Most common pathogenic variant
- Similar to idiopathic PD
- Possible earlier onset
Rare Variants:
- Variable expressivity
- Often family-specific
- May have additional features
For Carriers:
- 50% chance of passing variant
- Variable penetrance
- No completely predictive testing
For Family Members:
- Cascade screening available
- Genetic counseling recommended
- Research participation opportunities
¶ Research and Therapeutics
Retromer Stabilizers:
- Small molecules enhancing retromer function
- R55 and related compounds
- Preclinical development
Gene Therapy:
- AAV-VPS35 delivery
- Wild-type VPS35 expression
- Preclinical and early clinical stages
Protein-Based Therapy:
- Recombinant VPS35 protein
- Delivery challenges
- Research phase
Genetic Markers:
- Variant identification
- Family screening
- Research use
Fluid Biomarkers:
- CSF markers under investigation
- Lysosomal function tests
- Neurofilament levels
Imaging Biomarkers:
- Dopaminergic imaging
- Structural MRI
- Functional studies
Cell Lines:
- HEK293T for basic studies
- Neuronal cell lines (SH-SY5Y)
- Induced neurons from patients
Patient-Derived Models:
- Induced pluripotent stem cells (iPSCs)
- Dopaminergic neurons
- Isogenic controls
Mouse Models:
- Vps35 D620N knock-in
- Conditional knockout
- Transgenic overexpression
Zebrafish:
- Morpholino knockdown
- Transgenic models
- High-throughput screening
Drosophila:
- Homolog studies
- Transgenic expression
- Behavioral assays
VPS35 is highly conserved across species:
Orthologs:
- Mouse (99% identity)
- Zebrafish (92% identity)
- Drosophila (80% identity)
- Yeast (VPS35/SNX5/6)
Conservation Analysis:
- Essential residues in protein
- Domain structure preserved
- Functional motifs conserved
In Yeast:
- VPS35 ortholog
- Part of retromer complex
- Essential for viability
In Other Species:
- Multiple retromer components
- Accessory proteins
- Related trafficking factors
- Mechanistic Studies: Detailed molecular pathways
- Therapeutic Development: Drug discovery and delivery
- Biomarker Research: Early detection and monitoring
- Clinical Trials: Translation of discoveries
- Single-cell analysis: Cell-type specific effects
- Systems biology: Network-level understanding
- Precision medicine: Personalized approaches
- Gene therapy: Viral vector development
Mechanistic Insights:
-
Endosomal Trafficking Defects
- Impaired retrieval of cargo proteins
- Altered endosome morphology
- Disrupted protein sorting
-
Protein Aggregation
- Reduced clearance of α-synuclein
- Enhanced aggregation propensity
- Mitochondrial dysfunction
-
Synaptic Dysfunction
- Impaired vesicle recycling
- Altered neurotransmitter release
- Synaptic protein mislocalization
-
Cellular Stress
- Increased oxidative stress
- Mitochondrial damage
- ER stress response
APP Processing:
- Retromer regulates APP trafficking
- Altered processing increases Aβ
- Therapeutic implications
Tau Pathology:
- Retromer affects tau clearance
- Potential for propagation
- Interaction with tauopathies
Iron Metabolism:
- DMT1 trafficking disrupted
- Iron accumulation in neurons
- Oxidative stress contribution
Vulnerability Factors:
- High metabolic demand
- Extensive axonal arborization
- α-synuclein expression
- Iron accumulation with age
Pathogenic Mechanisms:
- Impaired autophagic clearance
- Mitochondrial dysfunction
- Synaptic impairment
Memory Circuits:
- CA1 pyramidal neurons
- Dentate gyrus granule cells
- Synaptic plasticity
AD Relevance:
- Early vulnerability
- Memory dysfunction
- Therapeutic target
Layer-Specific Effects:
- Layer 5 pyramidal neurons
- Interneuron populations
- Cortico-cortical connections
Functional Implications:
- Executive function
- Sensory processing
- Motor control
Retromer Stabilizers:
- R55 compound family
- Enhanced brain penetration
- Lead optimization
Mechanism:
- Stabilize retromer-cargo interactions
- Enhance trafficking efficiency
- Reduce toxic protein accumulation
AAV Platforms:
- Serotype selection
- Promoter optimization
- Delivery route
Clinical Application:
- Neuronal targeting
- Sustained expression
- Safety considerations
- Retromer enhancement + autophagy induction
- Gene therapy + small molecules
- Symptomatic + disease-modifying
Evolutionary Conservation:
- Core retromer function preserved
- Accessory proteins diversified
- Disease mechanisms conserved
Model Advantages:
- Genetic tractability
- Rapid phenotyping
- Drug screening
iPSC-Derived Models:
- Patient-specific neurons
- Isogenic controls
- Disease modeling
Applications:
- Mechanism elucidation
- Drug testing
- Biomarker discovery
¶ VPS35 and Other Neurodegeneration Genes
With PD Genes:
- LRRK2: Phosphorylation of retromer
- GBA: Lysosomal trafficking coordination
- SNCA: Genetic interaction
- PINK1/Parkin: Mitophagy coordination
With AD Genes:
- APP: Trafficking regulation
- MAPT: Tau connections
- TREM2: Microglial function
Protein-Protein Interactions:
- Retromer as hub
- Multiple pathway integration
- Disease gene network
Functional Overlap:
- Shared pathways
- Compensatory mechanisms
- Therapeutic targets
When to Test:
- Early-onset PD (<60 years)
- Family history
- Atypical features
How to Test:
- Comprehensive sequencing
- Deletion/duplication analysis
- Variant interpretation
For Patients:
- Prognostic information
- Family counseling
- Trial eligibility
For Clinicians:
- Diagnostic confirmation
- Treatment guidance
- Research updates
¶ Research Landscape
Ongoing Studies:
- Retromer stabilizer trials
- Biomarker development
- Natural history studies
- Single-cell sequencing
- Proteomics approaches
- Advanced imaging
- Precision medicine approaches
- Combination therapies
- Prevention strategies