Struktur-Funktions Analyse der aktiven Zone in Drosophila

突触活动区(AZ)膜介导了钙离子触发的突触小泡(SVS)融合，并与大分子细胞癌有关。Cast/ERC家族成员Bruchilot(BRP)是一种200kD的卷曲状富含蛋白质，我们先前的研究表明，它对果蝇细胞基质(T-bar)的形成、钙通道聚集和图案化突触可塑性是必不可少的。我们最近的分析表明，BRP是T-bar的直接构建块，其N端介导钙通道聚集活动以提高囊泡释放概率，其非常C端连接SVS以允许它们在突触的广泛使用中有效地招募。我们发现了几种BRP亚型(85、170、190kD)，包含这些与短期可塑性相关的结构域中的一个或两个，这些结构域显然在果蝇的突触类型之间存在差异表达。我们现在计划进一步描述BRP类型的亚型谱，并建立对这些亚型的特定遗传途径。此外，这些异构体应该在NMJ模型突触和基因工程果蝇的中央突触上进行功能表征(突触传递、短期可塑性、T-bar组装中的结构角色)。我们希望这个项目为从基因上重新设计BRP亚型奠定基础，以允许果蝇CNS和PNS的特定突触群体的功能表现(特别是短期可塑性)的明确变化。

Synaptic active zone (AZ) membranes mediate the Ca2+-triggered fusion of synaptic vesicles (SVs) and are associated with macromolecular cytomatrices. CAST/ERCfamily member Bruchpilot (BRP), a coiled-coil rich protein of 200 kD, we previously showed to be essential for cytomatrix (T-bar) formation, Ca2+-channel clustering and patterned synaptic plasticity in Drosophila. Our recent analysis showed that BRP is a direct building block of T-bars, with its N-terminus mediating Ca2+-channel clustering activity for improved vesicle release probability and its very C-terminus end tethering SVs to allow their efficient recruitment during extensive synaptic use. Several BRP isoforms (85, 170, 190 kD) we found, containing either one or both of these shortterm plasticity-relevant domains, which obviously are differentially expressed between synapse-types of Drosophila. We now plan to further describe the isoform spectrum of BRP types and establish specific genetic access to these isoforms. Moreover, these isoforms shall be functionally characterized (synaptic transmission, short-term plasticity, structural role within T-bar assembly) at both, the NMJ model synapse as well as at central synapses of Drosophila of genetically engineered flies. We hope that this project prepares grounds to genetically re-engineer BRP isoforms to allow defined changes of functional performance (particularly short-term plasticity) at defined synapse populations of the Drosophila CNS and PNS.