Department of Chemistry, Massachusetts Institute of Technology, Cambridge, 02139, USA.
Cell. 2010 Oct 29;143(3):456-69. doi: 10.1016/j.cell.2010.09.025. Epub 2010 Oct 7.
The functions of trans-synaptic adhesion molecules, such as neurexin and neuroligin, have been difficult to study due to the lack of methods to directly detect their binding in living neurons. Here, we use biotin labeling of intercellular contacts (BLINC), a method for imaging protein interactions based on interaction-dependent biotinylation of a peptide by E. coli biotin ligase, to visualize neurexin-neuroligin trans-interactions at synapses and study their role in synapse development. We found that both developmental maturation and acute synaptic activity stimulate the growth of neurexin-neuroligin adhesion complexes via a combination of neurexin and neuroligin surface insertion and internalization arrest. Both mechanisms require NMDA receptor activity. We also discovered that disruption of activity-induced neurexin-neuroligin complex growth prevents recruitment of the AMPA receptor, a hallmark of mature synapses. Our results provide support for neurexin-neuroligin function in synapse maturation and introduce a general method to study intercellular protein-protein interactions.
突触前粘附分子（如神经连接蛋白和神经突黏附蛋白）的功能由于缺乏直接检测其在活神经元中结合的方法而难以研究。在这里，我们使用细胞间接触的生物素标记（BLINC），一种基于大肠杆菌生物素连接酶对肽的相互作用依赖性生物素化来成像蛋白质相互作用的方法，来可视化突触处的神经连接蛋白-神经突黏附蛋白的转相互作用，并研究它们在突触发育中的作用。我们发现，发育成熟和急性突触活动通过神经连接蛋白和神经突黏附蛋白表面插入和内化阻滞的组合，刺激神经连接蛋白-神经突黏附蛋白黏附复合物的生长。这两种机制都需要 NMDA 受体活性。我们还发现，破坏活性诱导的神经连接蛋白-神经突黏附蛋白复合物的生长会阻止 AMPA 受体的募集，而 AMPA 受体是成熟突触的标志。我们的结果为神经连接蛋白-神经突黏附蛋白在突触成熟中的功能提供了支持，并介绍了一种研究细胞间蛋白质-蛋白质相互作用的通用方法。
