PHOSPHO-REGULATION OF SYNAPTIC AND EXTRASYNAPTIC N-METHYL-D-ASPARTATE RECEPTORS IN ADULT HIPPOCAMPAL SLICES
PHOSPHO-REGULATION OF SYNAPTIC AND EXTRASYNAPTIC N-METHYL-D-ASPARTATE RECEPTORS IN ADULT HIPPOCAMPAL SLICES
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DOI：
10.1016/j.neuroscience.2008.11.006
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发表时间：
2009-02-18
期刊：
影响因子：
3.3
通讯作者：
Browning, M. D.
中科院分区：
文献类型：
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作者：
Goebel-Goody, S. M.;Davies, K. D.;Browning, M. D.
最近的证据表明，n -甲基- d -部分受体（NMDAR）的运输有助于海马突触可塑性。酪氨酸残基的磷酸化，特别是NR2B酪氨酸1472，似乎是阻止NMDAR内吞的机制，这表明酪氨酸磷酸化与NMDAR的表面表达呈正相关。我们实验室和其他人之前的工作已经证实，酪氨酸磷酸酶和激酶活性的调节改变了NMDARs的表面表达。然而，这些研究中描述的NMDAR表面表达的变化是在总表面膜和细胞内受体方面。在谷氨酸能突触的质膜内，存在不同的nmdar群体。也就是说，基于它们与突触后密度（PSD）和谷氨酸可利用性的关联，表面受体可以分为突触池和突触外池。在本研究中，我们利用亚细胞分离方法结合洗涤剂提取从成年大鼠海马切片中制备突触和突触外NMDARs。利用这种方法，我们研究了酪氨酸磷酸酶和src家族酪氨酸激酶（SFK）抑制剂如何调节这些不同NMDARs的磷酸化和定位。我们发现突触和突触外的NMDARs都受到酪氨酸磷酸酶和SFK抑制剂的调节；然而，亚基特异性和残留物特异性效应被观察到。具体来说，NR2B酪氨酸1472的磷酸化与突触NMDARs的富集有关，而NR2B酪氨酸1336的磷酸化与突触外NMDARs的富集有关。利用电生理方法，我们还揭示了这些抑制剂产生的生化修饰与NMDAR功能的相应变化有关。由Elsevier Ltd代表IBRO出版。
Recent evidence demonstrates that N-methyl-D-as-partate receptor (NMDAR) trafficking contributes to synaptic plasticity in the hippocampus. Phosphorylation of tyrosine residues, especially NR2B tyrosine 1472, appears to be a mechanism by which NMDAR endocytosis is prevented, suggesting that the tyrosine phosphorylation and surface expression of NMDARs are positively correlated. Previous work from our laboratory and others has confirmed that modulation of tyrosine phosphatase and kinase activity alters the surface expression of NMDARs. However, the changes in NMDAR surface expression described in those studies were in terms of total surface membrane versus intracellular receptors. Within the plasma membrane of glutamatergic synapses, distinct populations of NMDARs exist. Namely, receptors at the surface can be differentiated into synaptic and extrasynaptic pools based on their association with the postsynaptic density (PSD) and availability to glutamate. In the present study, we utilized a subcellular fractionation approach coupled with detergent extraction to prepare synaptic and extrasynaptic NMDARs from adult rat hippocampal slices. Using this method, we examined how tyrosine phosphatase and Src-family tyrosine kinase (SFK) inhibitors modulate the phosphorylation and localization of these different pools of NMDARs. We found that both synaptic and extrasynaptic NMDARs were modulated by tyrosine phosphatase and SFK inhibitors; however subunit- and residue-specific effects were observed. Specifically, phosphorylation of NR2B tyrosine 1472 was associated with enrichment of synaptic NMDARs, whereas phosphorylation of NR2B tyrosine 1336 was associated with enrichment of extrasynaptic NMDARs. Using electrophysiological methods, we also reveal that the biochemical modifications produced by these inhibitors were associated with corresponding changes in NMDAR function. Published by Elsevier Ltd on behalf of IBRO.