Han Tae Hee, Vicidomini Rosario, Ramos Cathy Isaura, Mayer Mark, Serpe Mihaela
Section on Cellular Communication, Eunice Kennedy Shiver National Institute of Child Health and Human Development, NIH, Bethesda, MD, 20892, USA.
current address: The Institute of Functional Genomics of Lyon, 69007 Lyon, France.
bioRxiv. 2024 Apr 26:2024.04.22.590603. doi: 10.1101/2024.04.22.590603.
The formation of functional synapses requires co-assembly of ion channels with their accessory proteins which controls where, when, and how neurotransmitter receptors function. The auxiliary protein Neto modulates the function of kainate-type glutamate receptors in vertebrates as well as at the neuromuscular junction (NMJ), a glutamatergic synapse widely used for genetic studies on synapse development. We previously reported that Neto is essential for the synaptic recruitment and function of glutamate receptors. Here, using outside-out patch-clamp recordings and fast ligand application, we examine for the first time the biophysical properties of recombinant NMJ receptors expressed in HEK293T cells and compare them with native receptor complexes of genetically controlled composition. The two Neto isoforms, Neto-α and Neto-β, differentially modulate the gating properties of NMJ receptors. Surprisingly, we found that deactivation is extremely fast and that the decay of synaptic currents resembles the rate of iGluR desensitization. The functional analyses of recombinant iGluRs that we report here should greatly facilitate the interpretation of compound phenotypes of mutant animals.
功能性突触的形成需要离子通道与其辅助蛋白共同组装，这控制着神经递质受体在何处、何时以及如何发挥作用。辅助蛋白Neto在脊椎动物以及神经肌肉接头（NMJ）中调节红藻氨酸型谷氨酸受体的功能，神经肌肉接头是一种广泛用于突触发育遗传学研究的谷氨酸能突触。我们之前报道过，Neto对于谷氨酸受体的突触募集和功能至关重要。在这里，我们使用外向膜片钳记录和快速配体施加，首次研究了在HEK293T细胞中表达的重组NMJ受体的生物物理特性，并将它们与基因组成受控制的天然受体复合物进行比较。两种Neto亚型，Neto-α和Neto-β，对NMJ受体的门控特性有不同的调节作用。令人惊讶的是，我们发现失活极其迅速，并且突触电流的衰减类似于离子型谷氨酸受体脱敏的速率。我们在此报告的重组离子型谷氨酸受体的功能分析应极大地有助于解释突变动物的复合表型。
