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Dimeric structures of alpha-synuclein bind preferentially to lipid membranes
Eleni Giannakis1, Jessica Pacífico, David P Smith
1The Howard Florey Institute of Medical Research, Australia.
Biochimica Et Biophysica Acta
|February 12, 2008
Summary
Dimeric forms of alpha-synuclein, including wild type and Parkinson's disease mutants A53T and A30P, effectively bind lipid membranes. This interaction, crucial for Parkinson's disease, involves membrane penetration and perturbation by these protein species.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Alpha-synuclein aggregation and membrane binding are implicated in Parkinson's disease pathogenesis.
- Understanding the interaction of alpha-synuclein variants with lipid membranes is crucial for disease mechanism elucidation.
Purpose of the Study:
- To investigate the lipid binding characteristics of wild-type (Wt) alpha-synuclein and its familial mutants (A53T, A30P).
- To explore how these alpha-synuclein species interact with and perturb lipid membranes.
Main Methods:
- Development of a novel lipid binding assay utilizing surface-enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF MS).
- Tapping mode atomic force microscopy (AFM) imaging to visualize protein-lipid interactions at the membrane level.
Main Results:
- Wt and A53T alpha-synuclein showed high affinity binding of monomeric and dimeric species to lipid surfaces, with preferential binding by dimers.
- A30P mutant displayed low affinity for monomers but higher affinity for dimeric species, with larger oligomers undetected.
- AFM revealed Wt and mutant alpha-synuclein can penetrate lipid membranes, disrupt lipid layers, and bind to the underlying hydrophobic layer, consistent with monomeric and dimeric forms.
Conclusions:
- Dimeric species of Wt and familial mutant alpha-synucleins exhibit significant lipid binding capabilities.
- These dimeric forms are capable of causing membrane perturbations, contributing to Parkinson's disease pathology.
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