Proteomic Analysis of Unbounded Cellular Compartments: Synaptic Clefts

Area of Science:

• Neuroscience
• Proteomics
• Cell Biology

Background:

• Characterizing cellular compartments that resist biochemical isolation, such as synaptic clefts, presents significant challenges.
• Synaptic clefts are crucial for neural communication, mediating the balance between excitatory and inhibitory signaling essential for normal brain function.

Purpose of the Study:

• To proteomically characterize the synaptic clefts of both excitatory and inhibitory synapses in living neurons.
• To identify molecular differences between these synaptic cleft types and discover novel synaptic proteins.

Main Methods:

• Utilized a spatially restricted enzymatic tagging strategy to map protein composition.
• Applied advanced proteomic techniques to analyze synaptic clefts in situ within living neurons.

Main Results:

• Successfully mapped the proteomes of common excitatory and inhibitory synaptic clefts.
• Identified dozens of potential synaptic candidate proteins and assigned known synaptic proteins to specific cleft types.
• Revealed molecular differentiation between excitatory and inhibitory synaptic clefts.

Conclusions:

• The proteomic data provides a detailed molecular inventory of synaptic clefts.
• Identified Mdga2 as a potential specificity factor involved in Neuroligin-2 recruitment at inhibitory synapses.
• This work advances our understanding of synaptic function and the molecular basis of neural circuit balance.