Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea.
FEBS Lett. 2013 Nov 15;587(22):3668-74. doi: 10.1016/j.febslet.2013.09.027. Epub 2013 Sep 27.
Eukaryotic translation initiation factor 3 is composed of 13 subunits (eIF3a through eIF3m) and plays an essential role in translation. During apoptosis, several caspases rapidly down-regulate protein synthesis by cleaving eIF4G, -4B, -3j, and -2α. In this study, we found that the activation of caspases by cisplatin in T24 cells induces the cleavage of subunit G of the eIF3 complex (eIF3g). The cleavage site (SLRD(220)G) was identified, and we found that the cleaved N-terminus was translocated to the nucleus, activating caspase-3, and that it also showed a strong DNase activity. These data demonstrate the important roles of eIF3g in the translation initiation machinery and in DNA degradation during apoptosis.
真核翻译起始因子 3 由 13 个亚基（eIF3a 到 eIF3m）组成，在翻译中起着至关重要的作用。在细胞凋亡过程中，几种半胱天冬酶通过切割 eIF4G、-4B、-3j 和 -2α 迅速下调蛋白质合成。在这项研究中，我们发现顺铂在 T24 细胞中激活半胱天冬酶诱导真核翻译起始因子 3 复合物亚基 G 的切割（eIF3g）。鉴定到了切割位点（SLRD(220)G），我们发现切割产生的 N 端转移到细胞核，激活半胱天冬酶-3，并显示出强烈的 DNA 酶活性。这些数据表明 eIF3g 在翻译起始机制以及细胞凋亡过程中的 DNA 降解中发挥着重要作用。
