DiSFeB, Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy.
J Neurochem. 2015 Jan;132(2):159-68. doi: 10.1111/jnc.12968. Epub 2015 Jan 4.
Zinc (Zn(2+) ) is believed to play a relevant role in the physiology and pathophysiology of the brain. Hence, Zn(2+) homeostasis is critical and involves different classes of molecules, including Zn(2+) transporters. The ubiquitous Zn(2+) transporter-1 (ZNT-1) is a transmembrane protein that pumps cytosolic Zn(2+) to the extracellular space, but its function in the central nervous system is not fully understood. Here, we show that ZNT-1 interacts with GluN2A-containing NMDA receptors, suggesting a role for this transporter at the excitatory glutamatergic synapse. First, we found that ZNT-1 is highly expressed at the hippocampal postsynaptic density (PSD) where NMDA receptors are enriched. Two-hybrid screening, coimmunoprecipitation experiments and clustering assay in COS-7 cells demonstrated that ZNT-1 specifically binds the GluN2A subunit of the NMDA receptor. GluN2A deletion mutants and pull-down assays indicated GluN2A(1390-1464) domain as necessary for the binding to ZNT-1. Most importantly, ZNT-1/GluN2A complex was proved to be dynamic, since it was regulated by induction of synaptic plasticity. Finally, modulation of ZNT-1 expression in hippocampal neurons determined a significant change in dendritic spine morphology, PSD-95 clusters and GluN2A surface levels, supporting the involvement of ZNT-1 in the dynamics of excitatory PSD. Zn(2+) transporter-1 (ZNT-1) pumps cytosolic Zn(2+) to the extracellular space, but its function in the central nervous system is not fully understood. We show that ZNT-1 interacts with GluN2A-containing NMDA receptors at the glutamatergic synapse. Most importantly, ZNT-1/GluN2A complex is regulated by induction of synaptic plasticity. Modulation of ZNT-1 expression in hippocampal neurons determined a shrinkage of dendritic spines and a reduction of GluN2A surface levels supporting the involvement of ZNT-1 in the dynamics of the excitatory synapse.
锌（Zn(2+)）被认为在大脑的生理和病理生理学中发挥重要作用。因此，Zn(2+)的动态平衡至关重要，涉及包括 Zn(2+)转运体在内的不同分子类别。普遍存在的 Zn(2+)转运体-1（ZNT-1）是一种跨膜蛋白，可将细胞质中的 Zn(2+)泵入细胞外空间，但它在中枢神经系统中的功能尚未完全阐明。在这里，我们发现 ZNT-1 与含有 GluN2A 的 NMDA 受体相互作用，这表明该转运体在兴奋性谷氨酸能突触中具有作用。首先，我们发现 ZNT-1 在富含 NMDA 受体的海马突触后密度（PSD）中高度表达。双杂交筛选、共免疫沉淀实验和 COS-7 细胞中的聚类分析表明，ZNT-1 特异性结合 NMDA 受体的 GluN2A 亚基。GluN2A 缺失突变体和下拉实验表明，GluN2A(1390-1464)结构域是与 ZNT-1 结合所必需的。最重要的是，ZNT-1/GluN2A 复合物是动态的，因为它受突触可塑性诱导的调节。最后，在海马神经元中调节 ZNT-1 的表达会导致树突棘形态、PSD-95 簇和 GluN2A 表面水平发生显著变化，支持 ZNT-1 参与兴奋性 PSD 的动态变化。Zn(2+)转运体-1（ZNT-1）将细胞质中的 Zn(2+)泵入细胞外空间，但它在中枢神经系统中的功能尚未完全阐明。我们发现 ZNT-1 在谷氨酸能突触处与含有 GluN2A 的 NMDA 受体相互作用。最重要的是，ZNT-1/GluN2A 复合物受突触可塑性诱导的调节。在海马神经元中调节 ZNT-1 的表达会导致树突棘收缩和 GluN2A 表面水平降低，支持 ZNT-1 参与兴奋性突触的动态变化。
