Struktur-Funktions Analyse der aktiven Zone in Drosophila

突触活性区（AZ）膜介导Ca2+触发的突触囊泡（SVs）融合，并与大分子细胞瘤有关。CAST/ erc家族成员brchpilot （BRP）是一种200 kD的卷曲卷曲蛋白，我们之前在果蝇中发现它对细胞基质（T-bar）形成、Ca2+通道聚集和突触模式可塑性至关重要。我们最近的分析表明，BRP是t -棒的直接组成部分，其n端介导Ca2+通道聚集活性，以提高囊泡释放概率，其非常c端系住SVs，使其在广泛的突触使用中有效募集。我们发现了几种BRP亚型（85、170、190 kD），它们含有这些短期可塑性相关结构域中的一个或两个，这些结构域在果蝇突触类型之间的表达存在明显差异。我们现在计划进一步描述BRP类型的同工异构体谱，并建立这些同工异构体的特定遗传途径。此外，这些同工异构体在NMJ模型突触和转基因果蝇的中心突触都具有功能特征（突触传递、短期可塑性、T-bar组装中的结构作用）。我们希望该项目为基因重组BRP同种异构体奠定基础，从而在果蝇中枢神经系统和PNS的特定突触群体中允许功能性能（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.