Yavuzer U, Smith G C, Bliss T, Werner D, Jackson S P
Wellcome Trust/Cancer Research Campaign Institute of Cancer and Developmental Biology and Department of Zoology, Cambridge University, Cambridge CB2 1QR, UK.
Genes Dev. 1998 Jul 15;12(14):2188-99. doi: 10.1101/gad.12.14.2188.
DNA-dependent protein kinase (DNA-PK), which is involved in DNA double-strand break repair and V(D)J recombination, is comprised of a DNA-targeting component termed Ku and an approximately 465-kD catalytic subunit, DNA-PKcs. Although DNA-PK phosphorylates proteins in the presence of DSBs or other discontinuities in the DNA double helix in vitro, the possibility exists that it is also activated in other circumstances via its association with additional proteins. Here, through use of the yeast two-hybrid screen, we discover that the recently identified high affinity DNA binding protein C1D interacts with the putative leucine zipper region of DNA-PKcs. Furthermore, we show that C1D can interact with DNA-PK in mammalian cells and that C1D is a very effective DNA-PK substrate in vitro. Finally, we establish that C1D directs the activation of DNA-PK in a manner that does not require DNA termini. Therefore, these studies provide a function for C1D and suggest novel mechanisms for DNA-PK activation in vivo.
DNA依赖性蛋白激酶（DNA-PK）参与DNA双链断裂修复和V（D）J重组，由一个称为Ku的DNA靶向成分和一个约465-kD的催化亚基DNA-PKcs组成。尽管DNA-PK在体外双链DNA存在双链断裂（DSB）或其他间断的情况下可使蛋白质磷酸化，但它也有可能在其他情况下通过与其他蛋白质结合而被激活。在这里，通过酵母双杂交筛选，我们发现最近鉴定出的高亲和力DNA结合蛋白C1D与DNA-PKcs的假定亮氨酸拉链区域相互作用。此外，我们表明C1D可以在哺乳动物细胞中与DNA-PK相互作用，并且C1D在体外是一种非常有效的DNA-PK底物。最后，我们确定C1D以一种不需要DNA末端的方式指导DNA-PK的激活。因此，这些研究揭示了C1D的功能，并提出了体内DNA-PK激活的新机制。
