Efficient nuclear export of p65-IκBα complexes requires 14-3-3 proteins
Efficient nuclear export of p65-IκBα complexes requires 14-3-3 proteins
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DOI：
10.1242/jcs.03086
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发表时间：
2006-09-01
影响因子：
4
通讯作者：
Espinosa, Lluis
中科院分区：
文献类型：
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作者：
Aguilera, Cristina;Fernandez-Majada, Vanessa;Espinosa, Lluis
I kappa B 负责在非刺激条件下将 p65 维持在细胞质中，并在 NF kappa B 激活后促进 p65 从细胞核主动输出以终止信号。我们现在证明 14-3-3 蛋白通过与 p65 和 I kappa B α 蛋白物理相互作用来调节 NF kappa B 信号通路。我们鉴定了 p65 蛋白中涉及残基 38-44 和 278-283 的两个功能性 14-3-3 结合域，并绘制了残基 60-65 中 I kappa B α 的相互作用区域。 p65 或 I kappa B α 中这些 14-3-3 结合域的突变导致两种蛋白质主要分布在核内。 TNF α 处理促进 14-3-3 和 I kappa B α 募集至 NF kappa B 依赖性启动子，并增强 14-3-3 与 p65 的结合。通过显性失活 14-3-3 转染破坏 14-3-3 活性会导致核 p65-I kappa B α 复合物的积累以及 p65 与染色质的组成性关联。在这种情况下，NF kappa B 依赖性基因对 TNF α 刺激变得无反应。我们的结果共同表明，14-3-3 蛋白促进 I kappa B α-p65 复合物的核输出，并且是适当调节 NF kappa B 信号传导所必需的。
I kappa B are responsible for maintaining p65 in the cytoplasm under non-stimulating conditions and promoting the active export of p65 from the nucleus following NF kappa B activation to terminate the signal. We now show that 14-3-3 proteins regulate the NF kappa B signaling pathway by physically interacting with p65 and I kappa B alpha proteins. We identify two functional 14-3-3 binding domains in the p65 protein involving residues 38-44 and 278-283, and map the interaction region of I kappa B alpha in residues 60-65. Mutation of these 14-3-3 binding domains in p65 or I kappa B alpha results in a predominantly nuclear distribution of both proteins. TNF alpha treatment promotes recruitment of 14-3-3 and I kappa B alpha to NF kappa B-dependent promoters and enhances the binding of 14-3-3 to p65. Disrupting 14-3-3 activity by transfection with a dominant-negative 14-3-3 leads to the accumulation of nuclear p65-I kappa B alpha complexes and the constitutive association of p65 with the chromatin. In this situation, NF kappa B-dependent genes become unresponsive to TNF alpha stimulation. Together our results indicate that 14-3-3 proteins facilitate the nuclear export of I kappa B alpha-p65 complexes and are required for the appropriate regulation of NF kappa B signaling.