Arenzana-Seisdedos F, Turpin P, Rodriguez M, Thomas D, Hay R T, Virelizier J L, Dargemont C
Unité d'Immunologie Virale, Institut Pasteur, Paris, France.
J Cell Sci. 1997 Feb;110 ( Pt 3):369-78. doi: 10.1242/jcs.110.3.369.
I kappa B alpha tightly regulates the transcriptional activity of NF-kappa B by retaining it in the cytoplasm in an inactive form. In the present work, we report that I kappa B alpha, when expressed in the nuclear compartment, not only abrogates NF-kappa B/DNA interactions and NF-kappa B-dependent transcription, but also transports NF-kappa B back to the cytoplasm. This function of I kappa B alpha is insured by a nuclear export sequence located in the C-terminal domain of I kappa B alpha and homologous to the previously described export signal found in HIV-1 Rev protein as well as in PKI (the inhibitor of the catalytic subunit of protein kinase A). Thus, inhibition of NF-kappa B/DNA binding and the consecutive efficient nuclear export of the transcription factor of I kappa B alpha could represent an important mechanism for the control of the expression of NF-kappa B-dependent genes.
IκBα通过将NF-κB以无活性形式滞留在细胞质中，紧密调节其转录活性。在本研究中，我们报道，当IκBα在核区室中表达时，它不仅消除NF-κB与DNA的相互作用以及NF-κB依赖的转录，还将NF-κB转运回细胞质。IκBα的这一功能由位于IκBα C端结构域的核输出序列所保障，该序列与先前在HIV-1 Rev蛋白以及PKI（蛋白激酶A催化亚基的抑制剂）中发现的输出信号同源。因此，抑制NF-κB与DNA的结合以及随后IκBα转录因子高效的核输出可能代表了控制NF-κB依赖基因表达的一种重要机制。
