Multiple RIBEYE-RIBEYE interactions create a dynamic scaffold for the formation of synaptic ribbons
Multiple RIBEYE-RIBEYE interactions create a dynamic scaffold for the formation of synaptic ribbons
复制标题
DOI：
10.1523/jneurosci.1964-08.2008
复制
发表时间：
2008-08-06
影响因子：
5.3
通讯作者：
Schmitz, Frank
中科院分区：
文献类型：
--
作者：
Magupalli, Venkat Giri;Schwarz, Karin;Schmitz, Frank
突触带是带状突触活动区复合体中的大型动态结构，对这些紧张性活动突触的生理特性非常重要。RIBEYE是突触带的独特和主要的蛋白质组分。本研究的目的是了解突触带是如何构建的，以及突触带的构建如何有助于其超微结构的可塑性。在本研究中，我们使用不同的独立方法（酵母双杂交分析，蛋白质唐斯，突触带- RIBEYE相互作用测定，共聚集实验，透射电子显微镜和免疫金电子显微镜）证明RIBEYE自缔合. RIBEYE的A-结构域[ RIBEYE（A）]和B-结构域[ RIBEYE（B）]含有5个不同的RIBEYE-RIBEYE相互作用位点. RIBEYE的A结构域中存在三个相互作用位点，并介导RIBEYE（A）- RIBEYE（A）与B结构域的同源二聚化和异源二聚化。RIBEYE（A）在RIBEYE（B）上的对接位点在形貌和功能上不同于RIBEYE（B）同源二聚化界面，并且受烟酰胺腺嘌呤二核苷酸负调控。所鉴定的多种RIBEYE-RIBEYE相互作用具有构建突触带的潜力：异源表达的RIBEYE形成大的电子致密聚集体，其部分与周围的囊泡和膜隔室物理相关.这些结构类似于球形突触带。这些带状结构与活性区蛋白巴松管（RIBEYE在带状突触的活性区的相互作用伴侣）共组装，强调了这些含RIBEYE的聚集体的生理相关性。基于所确定的多种RIBEYE-RIBEYE相互作用，我们提供了一种从单个RIBEYE亚基动态组装突触带的分子机制。
Synaptic ribbons are large, dynamic structures in the active zone complex of ribbon synapses and important for the physiological properties of these tonically active synapses. RIBEYE is a unique and major protein component of synaptic ribbons. The aim of the present study was to understand how the synaptic ribbon is built and how the construction of the ribbon could contribute to its ultrastructural plasticity. In the present study, we demonstrate that RIBEYE self- associates using different independent approaches ( yeast two- hybrid analyses, protein pull downs, synaptic ribbon - RIBEYE interaction assays, coaggregation experiments, transmission electron microscopy and immunogold electron microscopy). The A- domain [ RIBEYE( A)] and B- domain [ RIBEYE( B)] of RIBEYE contain five distinct sites for RIBEYE - RIBEYE interactions. Three interaction sites are present in the A- domain of RIBEYE and mediate RIBEYE( A) - RIBEYE( A) homodimerization and heterodimerization with the B- domain. The docking site for RIBEYE( A) on RIBEYE( B) is topographically and functionally different from the RIBEYE( B) homodimerization interface and is negatively regulated by nicotinamide adenine dinucleotide. The identified multiple RIBEYE - RIBEYE interactions have the potential to build the synaptic ribbon: heterologously expressed RIBEYE forms large electron- dense aggregates that are in part physically associated with surrounding vesicles and membrane compartments. These structures resemble spherical synaptic ribbons. These ribbon- like structures coassemble with the active zone protein bassoon, an interaction partner of RIBEYE at the active zone of ribbon synapses, emphasizing the physiological relevance of these RIBEYE- containing aggregates. Based on the identified multiple RIBEYE - RIBEYE interactions, we provide a molecular mechanism for the dynamic assembly of synaptic ribbons from individual RIBEYE subunits.