The molecular organization of presynaptic active zones during calcium influx–triggered neurotransmitter release is the focus of intense investigation. The Drosophila coiled-coil domain protein Bruchpilot (BRP) was observed in donut-shaped structures centered at active zones of neuromuscular synapses by using subdiffraction resolution STED (stimulated emission depletion) fluorescence microscopy. At brp mutant active zones, electron-dense projections (T-bars) were entirely lost, Ca 2+ channels were reduced in density, evoked vesicle release was depressed, and short-term plasticity was altered. BRP-like proteins seem to establish proximity between Ca 2+ channels and vesicles to allow efficient transmitter release and patterned synaptic plasticity.

Bruchpilot Promotes Active Zone Assembly, Ca 2+ Channel Clustering, and Vesicle Release