Regulation of neuronal voltage-gated sodium channels by the ubiquitin-protein ligases Nedd4 and Nedd4-2
Regulation of neuronal voltage-gated sodium channels by the ubiquitin-protein ligases Nedd4 and Nedd4-2
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DOI：
10.1074/jbc.m402820200
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发表时间：
2004-07-09
影响因子：
4.8
通讯作者：
Kumar, S
中科院分区：
文献类型：
--
作者：
Fotia, AB;Ekberg, J;Kumar, S
Nedd 4和Nedd 4 -2是已知调节包括受体和离子转运蛋白在内的许多膜蛋白的泛素-蛋白连接酶。Nedd 4和Nedd 4 -2对上皮Na+通道的调节通过上皮钠通道亚基的PY基序与Nedd 4/Nedd 4 -2 WW结构域之间的相互作用介导。本实施例用作Nedd 4和Nedd 4 -2调节其它含有PY基序的离子通道的模型。我们发现6个电压门控Na+通道的羧基端都含有典型的PY基序（PPXY），另外一个Na-V通道含有PY基序变体（LPXY）。我们不仅通过Far-Western分析证明Nedd 4和Nedd 4 -2与含有PY基序的Na-v通道相互作用，而且我们还表明这些通道具有保守的WW结构域结合特异性。我们进一步表明，一个中枢神经系统和一个外周神经系统衍生的Na+通道（Na（v）1.2和Na（v）1.7，分别）的羧基末端融合蛋白很容易被Nedd 4 -2泛素化。在非洲爪蟾卵母细胞中，Nedd 4 -2强烈抑制所有三种Na（v）s（Na（v）1.2、Na（v）1.7和Na（v）1.8）的活性。有趣的是，Nedd 4抑制Na（v）1.2和Na（v）1.7的活性，但是Na（v）1.8的弱抑制剂。我们的研究结果提供了证据，Nedd 4和Nedd 4 -2可能是体内特定神经元Na-v通道的关键调节因子。
Nedd4 and Nedd4-2 are ubiquitin-protein ligases known to regulate a number of membrane proteins including receptors and ion transporters. Regulation of the epithelial Na+ channel by Nedd4 and Nedd4-2 is mediated via interactions between the PY motifs of the epithelial sodium channel subunits and the Nedd4/Nedd4-2 WW domains. This example serves as a model for the regulation of other PY motif-containing ion channels by Nedd4 and Nedd4-2. We found that the carboxyl termini of the six voltage-gated Na+ (Na-v) channels contain typical PY motifs (PPXY), and a further Na-v contains a PY motif variant (LPXY). Not only did we demonstrate by Far-Western analysis that Nedd4 and Nedd4-2 interact with the PY motif-containing Na-v channels, but we also showed that these channels have conserved WW domain binding specificity. We further showed that the carboxyl termini fusion proteins of one central nervous system and one peripheral nervous system-derived Na+ channel (Na(v)1.2 and Na(v)1.7, respectively) are readily ubiquitinated by Nedd4-2. In Xenopus oocytes, Nedd4-2 strongly inhibited the activities of all three Na(v)s (Na(v)1.2, Na(v)1.7, and Na(v)1.8) tested. Interestingly, Nedd4 suppressed the activity of Na(v)1.2 and Na(v)1.7 but was a poor inhibitor of Na(v)1.8. Our results provide evidence that Nedd4 and Nedd4-2 are likely to be key regulators of specific neuronal Na-v channels in vivo.