Active Zone Localization of Presynaptic Calcium Channels Encoded by thecacophonyLocus ofDrosophila

Open Access
Publisher Website
Google Scholar
Abstract
Presynaptic calcium channels play a central role in chemical synaptic transmission by providing the calcium trigger for evoked neurotransmitter release. These voltage-gated calcium channels are composed of a primary structural subunit, α1, as well as auxiliary β and α2δ subunits. Our previous genetic, molecular, and functional analysis has shown that thecacophony(cac) gene encodes a primary presynaptic calcium channel α1 subunit inDrosophila. Here we report that transgenic expression of acac-encoded α1 subunit fused with enhanced green fluorescent protein efficiently rescuescaclethal mutations and allowsin vivoanalysis of calcium channel localization at active zones. The results reported here further characterize the primary role ofcac-encoded calcium channels in neurotransmitter release. In addition, these studies provide a unique genetic tool for live imaging of functional presynaptic calcium channelsin vivoand define a molecular marker for immunolocalization of other presynaptic proteins relative to active zones. These findings are expected to facilitate additional analysis of synaptic development and function in this important model system.