Binding of neuronal nitric-oxide synthase (nNOS) to carboxyl-terminal-binding protein (CtBP) changes the localization of CtBP from the nucleus to the cytosol - A novel function for targeting by the PDZ domain of nNOS
Binding of neuronal nitric-oxide synthase (nNOS) to carboxyl-terminal-binding protein (CtBP) changes the localization of CtBP from the nucleus to the cytosol - A novel function for targeting by the PDZ domain of nNOS
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DOI：
10.1074/jbc.m106503200
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发表时间：
2001-12-21
影响因子：
4.8
通讯作者：
Firestein, BL
中科院分区：
文献类型：
--
作者：
Riefler, GM;Firestein, BL
最近的研究表明 PDZ 结构域在将结合伴侣靶向细胞中的特定位点方面发挥着重要作用。为了确定神经元一氧化氮合酶 (nNOS) 的 PDZ 结构域是否可以发挥这样的作用，我们对脑提取物与 nNOS PDZ 结构域进行了亲和层析。我们鉴定了羧基末端结合蛋白 (CtBP)，这是一种磷蛋白，首先被鉴定为腺病毒 EIA 的结合伴侣，也是 nNOS 结合伴侣。 CtBP 与 nNOS 的 PDZ 结构域相互作用，并且这种相互作用可以与结合 PDZ 肽结合位点的肽竞争。此外，CtBP 与 nNOS 的结合取决于其羧基末端序列 -DXL，即物种间保守的残基。拟合 nNOS PDZ 结合的规范序列。免疫沉淀研究表明，CtBP 和 nNOS 在大脑中存在关联。当CtBP在Madin-Darby犬肾细胞中表达时，其分布主要在核；然而，当 CtBP 与 nNOS 共表达时，其定位变得更加胞质。当其羧基末端 nNOS PDZ 结合基序突变或当 CtBP 与突触后密度 95（另一种含有 PDZ 结构域的蛋白质）共表达时，CtBP 定位不会发生这种变化。综上所述，我们的数据表明 nNOS 作为 CtBP 核定位调节剂的新功能。
Recent work suggests a role for PDZ domains in the targeting of binding partners to specific sites in the cell. To identify whether the PDZ domain of neuronal nitric-oxide synthase (nNOS) can play such a role, we performed affinity chromatography of brain extract with the nNOS PDZ domain. We identified the carboxyl-terminal-binding protein (CtBP), a phosphoprotein first identified as a binding partner to adenovirus EIA, as a nNOS binding partner. CtBP interacts with the PDZ domain of nNOS, and this interaction can be competed with peptide that binds to the PDZ peptide-binding site. In addition, binding of CtBP to nNOS is dependent on its carboxyl-terminal sequence -DXL, residues conserved between species that. fit the canonical sequence for nNOS PDZ binding. Immunoprecipitation studies show that CtBP and nNOS associate in the brain. When CtBP is expressed in Madin-Darby canine kidney cells, its distribution is primarily nuclear; however, when CtBP is co-expressed with nNOS, its localization becomes more cytosolic. This change in CtBP localization does not occur when its carboxyl-terminal nNOS PDZ binding motif is mutated or when CtBP is co-expressed with postsynaptic density 95, another PDZ domain-containing protein. Taken together, our data suggest a new function for nNOS as a regulator of CtBP nuclear localization.