α-synuclein multimers cluster synaptic vesicles and attenuate recycling

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Alpha-synuclein (α-syn) is a presynaptic protein implicated in synaptic function and disease.
• Previous research indicated α-syn attenuates synaptic exocytosis and endocytosis, but mechanisms were unclear.
• Emerging evidence suggests α-syn exists in multimeric forms, not just as a monomer.

Purpose of the Study:

• To investigate the conformations of α-syn at synapses.
• To elucidate the role of α-syn higher-order structures in synaptic function.
• To understand the mechanisms by which α-syn influences synaptic vesicle dynamics.

Main Methods:

• Studied α-syn conformations and synaptic function in neuronal models.
• Utilized techniques to observe α-syn organization at synapses.
• Examined the impact of α-syn mutations on synaptic vesicle behavior and exocytosis/endocytosis.

Main Results:

• α-syn rapidly organizes into physiological multimers within synapses.
• α-syn multimers were found to cluster synaptic vesicles.
• Multimerization of α-syn was essential for restricting synaptic vesicle motility and attenuating exo/endocytosis.
• Mutations preventing α-syn multimerization abolished these effects.

Conclusions:

• α-syn exists and functions as physiological multimers at synapses.
• These α-syn multimers play a novel role in regulating synaptic vesicle clustering and motility.
• A proposed model suggests α-syn multimers restrict synaptic vesicle trafficking and recycling, thereby attenuating neurotransmitter release.