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Updated: Mar 31, 2026
A Method to Study α-Synuclein Toxicity and Aggregation Using a Humanized Yeast Model
Published on: November 25, 2022
O-GlcNAc modification blocks the aggregation and toxicity of the protein α-synuclein associated with Parkinson's
Nicholas P Marotta1, Yu Hsuan Lin1, Yuka E Lewis1
1Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA.
Abstract:
Several aggregation-prone proteins associated with neurodegenerative diseases can be modified by O-linked N-acetyl-glucosamine (O-GlcNAc) in vivo. One of these proteins, α-synuclein, is a toxic aggregating protein associated with synucleinopathies, including Parkinson's disease. However, the effect of O-GlcNAcylation on α-synuclein is not clear. Here, we use synthetic protein chemistry to generate both unmodified α-synuclein and α-synuclein bearing a site-specific O-GlcNAc modification at the physiologically relevant threonine residue 72. We show that this single modification has a notable and substoichiometric inhibitory effect on α-synuclein aggregation, while not affecting the membrane binding or bending properties of α-synuclein. O-GlcNAcylation is also shown to affect the phosphorylation of α-synuclein in vitro and block the toxicity of α-synuclein that was exogenously added to cells in culture. These results suggest that increasing O-GlcNAcylation may slow the progression of synucleinopathies and further support a general function for O-GlcNAc in preventing protein aggregation.
Insights
O-linked N-acetyl-glucosamine (O-GlcNAc) modification of alpha-synuclein inhibits its aggregation and toxicity. This finding suggests O-GlcNAcylation may slow neurodegenerative disease progression in synucleinopathies.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Aggregation-prone proteins, like alpha-synuclein, are linked to neurodegenerative diseases.
- Alpha-synuclein aggregation causes synucleinopathies, including Parkinson's disease.
- The role of O-linked N-acetyl-glucosamine (O-GlcNAc) modification in alpha-synuclein function is unclear.
Purpose of the Study:
- To investigate the effect of O-GlcNAcylation on alpha-synuclein aggregation and toxicity.
- To determine if site-specific O-GlcNAc modification impacts alpha-synuclein's biophysical properties.
- To explore the relationship between O-GlcNAcylation and alpha-synuclein phosphorylation.
Main Methods:
- Utilized synthetic protein chemistry to create unmodified and site-specifically O-GlcNAcylated alpha-synuclein.
- Assessed the impact of O-GlcNAcylation on alpha-synuclein aggregation kinetics.
- Examined the effects of O-GlcNAcylation on membrane binding, bending, and cellular toxicity.
Main Results:
- A single O-GlcNAc modification at threonine 72 substoichiometrically inhibited alpha-synuclein aggregation.
- O-GlcNAcylation did not alter alpha-synuclein's membrane binding or bending properties.
- O-GlcNAcylation affected alpha-synuclein phosphorylation in vitro and blocked its cellular toxicity.
Conclusions:
- Site-specific O-GlcNAcylation of alpha-synuclein inhibits its aggregation and toxicity.
- O-GlcNAcylation may represent a therapeutic strategy to slow synucleinopathy progression.
- O-GlcNAc modification generally functions to prevent protein aggregation.
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