Functional analysis of VPS41-mediated neuroprotection in Caenorhabditis elegans and mammalian models of Parkinson's disease.
Disruption of the lysosomal system has emerged as a key cellular pathway in the neurotoxicity of α-synuclein (α-syn) and the progression of Parkinson's disease (PD). A large-scale RNA interference (RNAi) screen using Caenorhabditis elegans identified VPS-41, a multidomain protein involved in lysosomal protein trafficking, as a modifier of α-syn accumulation and dopaminergic neuron degeneration (Hamamichi et al., 2008). Previous studies have shown a conserved neuroprotective function of human VPS41 (hVPS41) against PD-relevant toxins in mammalian cells and C. elegans neurons (Ruan et al., 2010). Here, we report that both the AP-3 (heterotetrameric adaptor protein complex) interaction domain and clathrin heavy-chain repeat domain are required for protecting C. elegans dopaminergic neurons from α-syn-induced neurodegeneration, as well as to prevent α-syn inclusion formation in an H4 human neuroglioma cell model. Using mutant C. elegans and neuron-specific RNAi, we revealed that hVPS41 requires both a functional AP-3 (heterotetrameric adaptor protein complex) and HOPS (homotypic fusion and vacuole protein sorting)-tethering complex to elicit neuroprotection. Interestingly, two nonsynonymous single-nucleotide polymorphisms found within the AP-3 interacting domain of hVPS41 attenuated the neuroprotective property, suggestive of putative susceptibility factors for PD. Furthermore, we observed a decrease in α-syn protein level when hVPS41 was overexpressed in human neuroglioma cells. Thus, the neuroprotective capacity of hVPS41 may be a consequence of enhanced clearance of misfolded and aggregated proteins, including toxic α-syn species. These data reveal the importance of lysosomal trafficking in maintaining cellular homeostasis in the presence of enhanced α-syn expression and toxicity. Our results support hVPS41 as a potential novel therapeutic target for the treatment of synucleinopathies like PD.
Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487, USA.
Adam J
AJ
Harrington
Talene A
TA
Yacoubian
Sunny R
SR
Slone
Kim A
KA
Caldwell
Guy A
GA
Caldwell
D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000502:physiology*; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics; D004195:Disease Models, Animal; D055786:Gene Knockout Techniques; D020022:Genetic Predisposition to Disease; D006801:Humans; D018696:Neuroprotective Agents / Q000378:metabolism*; D010300:Parkinson Disease / Q000235:genetics / Q000378:metabolism* / Q000517:prevention & control*; D055503:Protein Multimerization; D014157:Transcription Factors / Q000235:genetics; D033921:Vesicular Transport Proteins / Q000502:physiology*; D051844:alpha-Synuclein / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D004268:DNA-Binding Proteins; D018696:Neuroprotective Agents; D014157:Transcription Factors; C549959:VPS41 protein, human; D033921:Vesicular Transport Proteins; D051844:alpha-Synuclein; C060759:enhancer-binding protein AP-3