Endosomal Phosphatidylinositol 3-Phosphate Promotes Gephyrin Clustering and GABAergic Neurotransmission at Inhibitory Postsynapses
Endosomal Phosphatidylinositol 3-Phosphate Promotes Gephyrin Clustering and GABAergic Neurotransmission at Inhibitory Postsynapses
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DOI：
10.1074/jbc.m116.771592
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发表时间：
2017-01-27
影响因子：
4.8
通讯作者：
Betz, Heinrich
中科院分区：
文献类型：
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作者：
Papadopoulos, Theofilos;Rhee, Hong Jun;Betz, Heinrich
神经元突触的形成及其效能的动态调节依赖于突触后神经递质受体装置的正确组装。受体募集到抑制性GABA能后突触需要支架蛋白桥蛋白和鸟嘌呤核苷酸交换因子collybistin（Cb）。在体外，Cb的pleckstrin同源结构域结合磷酸肌醇，特别是3-磷酸磷脂酰肌醇（PI 3 P）。然而，目前尚不清楚PI3P是否是抑制性突触后形成所必需的。在这里，我们调查的作用，PI3P在开发GABA能突触后，通过使用膜渗透的PI3P衍生物，时间推移共聚焦成像，电生理学，以及敲低和过度表达的PI3P代谢酶。我们的研究结果提供了第一个在cellula证据表明，PI3P位于早期/排序内体调节突触后聚集的gephyrin和GABAA受体和强度的抑制，但不是兴奋性，突触后培养的海马神经元。在人胚肾293细胞中，通过PI3P刺激桥蛋白簇的形成依赖于Cb。因此，我们的结论是，由III类磷脂酰肌醇3-激酶产生的PI3P的内体池，是重要的Cb介导的招聘桥蛋白和GABAA受体发展抑制性突触后，从而形成突触后膜专业化。
The formation of neuronal synapses and the dynamic regulation of their efficacy depend on the proper assembly of the postsynaptic neurotransmitter receptor apparatus. Receptor recruitment to inhibitory GABAergic postsynapses requires the scaffold protein gephyrin and the guanine nucleotide exchange factor collybistin (Cb). In vitro, the pleckstrin homology domain of Cb binds phosphoinositides, specifically phosphatidylinositol 3-phosphate (PI3P). However, whether PI3P is required for inhibitory postsynapse formation is currently unknown. Here, we investigated the role of PI3P at developing GABAergic postsynapses by using a membrane-permeant PI3P derivative, time-lapse confocal imaging, electrophysiology, as well as knockdown and overexpression of PI3P-metabolizing enzymes. Our results provide the first in cellula evidence that PI3P located at early/sorting endosomes regulates the postsynaptic clustering of gephyrin and GABAA receptors and the strength of inhibitory, but not excitatory, postsynapses in cultured hippocampal neurons. In human embryonic kidney 293 cells, stimulation of gephyrin cluster formation by PI3P depends on Cb. We therefore conclude that the endosomal pool of PI3P, generated by the class III phosphatidylinositol 3-kinase, is important for the Cb-mediated recruitment of gephyrin and GABAA receptors to developing inhibitory postsynapses and thus the formation of postsynaptic membrane specializations.