Ca²⁺ channel and active zone protein abundance intersects with input-specific synapse organization to shape...

Area of Science:

• Neuroscience
• Molecular Biology
• Synaptic Plasticity

Background:

• Synaptic heterogeneity is crucial for complex neural circuit function.
• Understanding factors contributing to synapse diversity is essential for circuit analysis.

Purpose of the Study:

• To investigate how voltage-gated calcium channel (VGCC) abundance, organization, and subunit composition contribute to synapse diversity.
• To analyze differences among and between synapses formed by two related Drosophila glutamatergic motor neurons with distinct release probabilities (P_r).

Main Methods:

• Utilized endogenously tagged lines to study VGCC subunits in vivo.
• Quantified VGCC abundance, spatial organization, and active zone (AZ) protein levels.
• Assessed neurotransmitter release probability (P_r) at individual synapses.

Main Results:

• VGCC levels predict heterogeneous P_r within inputs, not between them.
• VGCCs are more densely organized at high-P_r synapses, indicating tighter coupling.
• α2δ-3 (Straightjacket) and Bruchpilot levels correlate positively with P_r and are dynamically regulated.

Conclusions:

• VGCC abundance, spatial organization, and AZ protein composition interact to shape synaptic functional diversity.
• This interplay contributes to adaptable communication in neural circuits.
• Findings suggest a model where VGCC and AZ protein dynamics modulate synapse function.