Reconstituted Postsynaptic Density as a Molecular Platform for Understanding Synapse Formation and Plasticity.

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• Synapses are crucial protein-dense compartments for neuronal signal processing.
• The molecular mechanisms governing synapse formation and dynamic regulation remain incompletely understood.
• Understanding synaptic assembly is fundamental to mammalian brain function.

Purpose of the Study:

• To elucidate the molecular basis of synaptic assembly and regulation.
• To investigate the role of scaffold proteins in forming postsynaptic density (PSD) structures.
• To develop a reconstituted system for studying synaptic molecular organization.

Main Methods:

• Utilized a biochemical reconstitution approach.
• Studied protein interactions in solution and on supported membrane bilayers.
• Analyzed phase separation dynamics of major excitatory postsynaptic density scaffold proteins.

Main Results:

• Multivalent interactions among scaffold proteins drive the formation of PSD-like assemblies via phase separation.
• Reconstituted assemblies effectively cluster receptors, concentrate enzymes, and promote actin bundle formation.
• These assemblies selectively exclude inhibitory postsynaptic proteins and exhibit distinct properties from homogeneous solutions.

Conclusions:

• Phase separation of scaffold proteins is a key mechanism for forming functional synaptic compartments.
• The reconstituted PSD assemblies mimic essential features of native synapses, supporting synaptic functions.
• This molecular platform provides novel insights into the formation and dynamic regulation of neuronal synapses.