Neurexin-1β Binding to Neuroligin-1 Triggers the Preferential Recruitment of PSD-95 versus Gephyrin through Tyrosine Phosphorylation of Neuroligin-1
Neurexin-1β Binding to Neuroligin-1 Triggers the Preferential Recruitment of PSD-95 versus Gephyrin through Tyrosine Phosphorylation of Neuroligin-1
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DOI：
10.1016/j.celrep.2013.05.013
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发表时间：
2013-06-01
期刊：
影响因子：
8.8
通讯作者：
Thoumine, Olivier
中科院分区：
文献类型：
--
作者：
Giannone, Gregory;Mondin, Magali;Thoumine, Olivier
神经素-1 β (Nrx1 β)和神经素-1 （Nlg1）之间的粘附诱导突触后密度蛋白95 （PSD-95）支架的早期募集；然而，相关的信号机制尚不清楚。为了分离配体结合和受体多聚的影响，我们比较了神经元中Nlg1与Nrx1 β或非激活HA抗体结合的条件。延时成像、光漂白后的荧光恢复以及单粒子跟踪表明，Nrx1 β结合除了聚集Nlg1外，还刺激了Nlg1与PSD-95之间的相互作用。磷酸化酪氨酸免疫印迹和Nlg1肽对格菲林的体外拉下实验表明，Nlg1可以磷酸化独特的酪氨酸（Y782），阻止格菲林的结合。Nlg1点突变体在神经元中的表达表明，Y782磷酸化控制了Nlg1与PSD-95的优先结合，从而形成抑制性和兴奋性突触。我们认为配体诱导的Nlg1磷酸酪氨酸水平的变化控制了突触形成和稳定过程中兴奋性和抑制性支架组装之间的平衡。
Adhesion between neurexin-1 beta (Nrx1 beta) and neuroligin- 1 (Nlg1) induces early recruitment of the postsynaptic density protein 95 (PSD-95) scaffold; however, the associated signaling mechanisms are unknown. To dissociate the effects of ligand binding and receptor multimerization, we compared conditions in which Nlg1 in neurons was bound to Nrx1 beta or non-activating HA antibodies. Time-lapse imaging, fluorescence recovery after photobleaching, and single-particle tracking demonstrated that in addition to aggregating Nlg1, Nrx1 beta binding stimulates the interaction between Nlg1 and PSD-95. Phosphotyrosine immunoblots and pull-down of gephyrin by Nlg1 peptides in vitro showed that Nlg1 can be phosphorylated at a unique tyrosine (Y782), preventing gephyrin binding. Expression of Nlg1 point mutants in neurons indicated that Y782 phosphorylation controls the preferential binding of Nlg1 to PSD-95 versus gephyrin, and accordingly the formation of inhibitory and excitatory synapses. We propose that ligand-induced changes in the Nlg1 phosphotyrosine level control the balance between excitatory and inhibitory scaffold assembly during synapse formation and stabilization.