Besse Florence, Mertel Sara, Kittel Robert J, Wichmann Carolin, Rasse Tobias M, Sigrist Stephan J, Ephrussi Anne
Developmental Biology Unit, European Molecular Biology Laboratory, D-69117 Heidelberg, Germany.
J Cell Biol. 2007 Jun 4;177(5):843-55. doi: 10.1083/jcb.200701111.
Synapses can undergo rapid changes in size as well as in their vesicle release function during both plasticity processes and development. This fundamental property of neuronal cells requires the coordinated rearrangement of synaptic membranes and their associated cytoskeleton, yet remarkably little is known of how this coupling is achieved. In a GFP exon-trap screen, we identified Drosophila melanogaster Basigin (Bsg) as an immunoglobulin domain-containing transmembrane protein accumulating at periactive zones of neuromuscular junctions. Bsg is required pre- and postsynaptically to restrict synaptic bouton size, its juxtamembrane cytoplasmic residues being important for that function. Bsg controls different aspects of synaptic structure, including distribution of synaptic vesicles and organization of the presynaptic cortical actin cytoskeleton. Strikingly, bsg function is also required specifically within the presynaptic terminal to inhibit nonsynchronized evoked vesicle release. We thus propose that Bsg is part of a transsynaptic complex regulating synaptic compartmentalization and strength, and coordinating plasma membrane and cortical organization.
在可塑性过程和发育过程中，突触的大小及其囊泡释放功能会发生快速变化。神经元细胞的这一基本特性需要突触膜及其相关细胞骨架的协调重排，但对于这种耦合是如何实现的，人们所知甚少。在一项绿色荧光蛋白（GFP）外显子捕获筛选中，我们鉴定出果蝇的Basigin（Bsg）是一种含免疫球蛋白结构域的跨膜蛋白，它在神经肌肉接头的活动区周围积累。突触前和突触后都需要Bsg来限制突触小体的大小，其近膜细胞质残基对该功能很重要。Bsg控制突触结构的不同方面，包括突触囊泡的分布和突触前皮质肌动蛋白细胞骨架的组织。引人注目的是，在突触前终末内也特别需要bsg功能来抑制非同步诱发的囊泡释放。因此，我们提出Bsg是调节突触分隔和强度以及协调质膜和皮质组织的跨突触复合体的一部分。
