CAST/ELKS-endophilin-A interaction ensures synaptic vesicle pool size

Area of Science:

• Neuroscience
• Cell Biology
• Molecular Biology

Background:

• Efficient neurotransmission depends on synaptic vesicle (SV) recycling at presynaptic terminals.
• The molecular mechanisms governing SV dynamics and pool maintenance are not fully understood.

Purpose of the Study:

• To investigate the role of active zone proteins CAST and ELKS in SV recycling and presynaptic function.
• To elucidate the interaction between CAST/ELKS and endophilin-A family proteins in regulating SV pool size.

Main Methods:

• Primary hippocampal neuron cultures were used.
• Disruption of CAST binding to endophilin-A was induced.
• Synaptic vesicle pools, protein localization (endophilin-A, clathrin light chain, active zone proteins), and expression levels were analyzed.

Main Results:

• Disruption of CAST-endophilin-A interaction led to a smaller functional SV pool.
• Endophilin-A mislocalization and altered clathrin light chain presynaptic localization were observed.
• Reduced endophilin-A levels impacted active zone protein expression.

Conclusions:

• CAST and ELKS are critical for maintaining the functional SV pool size through their interaction with endophilin-A.
• This interaction is essential for sustained synaptic transmission by ensuring adequate SV availability.
• The findings expand the known functions of CAST/ELKS beyond structural roles in the active zone.