Evidence for direct protein kinase-C mediated modulation of N-methyl-D-aspartate receptor current
Evidence for direct protein kinase-C mediated modulation of N-methyl-D-aspartate receptor current
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DOI：
10.1124/mol.59.5.960
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发表时间：
2001-05-01
影响因子：
3.6
通讯作者：
Leonard, JP
中科院分区：
文献类型：
--
作者：
Liao, GY;Wagner, DA;Leonard, JP
蛋白激酶C（PKC）激活不同地影响N-甲基-D-天冬氨酸（NMDA）型谷氨酸受体的电流，这取决于它们的亚基组成。使用嵌合体的实验最初表明，NR 2B（对PKC有反应）和NR 2C（对PKC无反应）亚基的细胞质C-末端尾含有导致观察到的PKC效应差异的氨基酸残基。然而，截短和点突变实验表明，PKC对NMDA受体的作用可能是完全间接的，通过相关蛋白的磷酸化起作用。在这里，我们认为，PKC确实，事实上，影响NR 2B/NR 1 -011 NMDA电流的直接磷酸化的NR 2B尾巴在残基S1303和S1323。用Ala替换这些残基中的任何一个都会严重降低PKC增强作用。为了验证S1303和S1323是PKC直接磷酸化的位点，将来自这些位点周围区域的合成肽用作纯化的大鼠脑PKC体外测定的底物。这些结果表明，PKC可直接磷酸化NR 2B C端的S1303和S1323，导致通过NMDA受体通道的电流增强。PKC对某些NMDA受体亚型的直接作用在PKC和NR 2B/NR 1受体相互作用的任何生理或病理过程中可能是重要的。
Protein kinase-C (PKC) activation differentially affects currents from N-methyl-D-aspartate (NMDA) type glutamate receptors depending upon their subunit composition. Experiments using chimeras initially indicated that the cytoplasmic C-terminal tails of NR2B (responsive to PKC) and NR2C (unresponsive to PKC) subunits contain the amino acid residues responsible for the observed disparity of PKC effects. However, truncation and point mutation experiments have suggested that PKC action on NMDA receptors may be entirely indirect, working via the phosphorylation of associated proteins. Here we suggest that PKC does, in fact, affect NR2B/NR1-011 NMDA currents by direct phosphorylation of the NR2B tail at residues S1303 and S1323. Replacement of either of these residues with Ala severely reduces PKC potentiation. To verify that S1303 and S1323 are sites of direct phosphorylation by PKC, synthetic peptides from the regions surrounding these sites were used as substrates for in vitro assays with purified rat brain PKC. These results indicate that PKC can directly phosphorylate S1303 and S1323 in the NR2B C terminus, leading to enhanced currents through NMDA receptor channels. The direct action of PKC on certain NMDA receptor subtypes may be important in any physiological or pathological process where PKC and NR2B/NR1 receptors interact.