Mutation E46K increases phospholipid binding and assembly into filaments of human alpha-synuclein.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Familial Parkinson's disease and dementia with Lewy bodies are linked to alpha-synuclein mutations and protein overproduction.
• Alpha-synuclein forms Lewy bodies and neurites, key neuropathological hallmarks of these neurodegenerative diseases.
• A new missense mutation, E46K, in alpha-synuclein has been identified in an inherited form of dementia with Lewy bodies.

Purpose of the Study:

• To investigate the functional consequences of the E46K alpha-synuclein mutation.
• To determine the effects of E46K on phospholipid binding and filament assembly.
• To understand the potential role of E46K in the pathogenesis of neurodegenerative diseases.

Main Methods:

• Investigated alpha-synuclein's interaction with negatively charged liposomes.
• Assessed the rate and morphology of alpha-synuclein filament assembly in vitro.
• Compared the functional effects of E46K with wild-type and previously identified mutations (A30P, A53T).

Main Results:

• The E46K mutation significantly increased alpha-synuclein's binding affinity to negatively charged liposomes.
• E46K accelerated the rate of alpha-synuclein filament assembly, similar to the A53T mutation.
• Filaments formed by E46K alpha-synuclein exhibited a distinct twisted morphology.

Conclusions:

• The E46K mutation alters alpha-synuclein's biophysical properties, enhancing lipid binding and promoting filament formation.
• These functional changes provide a molecular basis for the pathogenicity of the E46K mutation in inherited dementia with Lewy bodies.
• The study highlights the critical role of alpha-synuclein's interaction with lipids in neurodegeneration.