Molecular and Cellular Pathobiology Cancer-Derived Mutations in KEAP 1 Impair NRF 2 Degradation but not Ubiquitination
Molecular and Cellular Pathobiology Cancer-Derived Mutations in KEAP 1 Impair NRF 2 Degradation but not Ubiquitination
复制标题
DOI：
--
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Bridgid E Hast;Erica W. Cloer;D. Goldfarb;Heng Li;P. F. Siesser;Feng Yan;Vonn Walter;N. Zheng;D. Hayes;Michael B. Major
中科院分区：
文献类型：
--
作者：
Bridgid E Hast;Erica W. Cloer;D. Goldfarb;Heng Li;P. F. Siesser;Feng Yan;Vonn Walter;N. Zheng;D. Hayes;Michael B. Major
NRF2是一种介导应激反应的转录因子。NRF2的致癌突变定位于其与KEAP1的两个结合界面之一，KEAP1是一种E3泛素连接酶，可促进NRF2的蛋白酶体依赖性降解。KEAP1的体细胞突变通常发生在人类癌症中，其中KEAP1可能作为肿瘤抑制因子发挥作用。这些突变分布在KEAP1蛋白中，但对其功能影响知之甚少。在这项研究中，我们鉴定了在肺鳞状细胞癌肿瘤组中定义的18个KEAP1突变。四个突变表现为野生型KEAP1，因此可能是乘客事件。R554Q、W544C、N469fs、P318fs和G333C突变减弱了NRF2的结合和抑制活性。其余突变表现出NRF2的亚形态抑制，同时结合NRF2和CUL3。蛋白质组学分析显示，R320Q、R470C、G423V、D422N、G186R、S243C和V155F突变增强了KEAP1与NRF2的结合。有趣的是，这些“超级粘合剂”突变体表现出NRF2的降解减少。基于细胞和体外生化分析表明，尽管R320Q“超结合剂”突变体无法抑制NRF2活性，但它保持了NRF2泛素化的能力。这些数据加强了KEAP1和NRF2在癌症中的遗传相互作用，并为KEAP1机制提供了新的见解。癌症Res;74 (3);808 - 17所示。2013 AACR。
NRF2 is a transcription factor that mediates stress responses. Oncogenic mutations in NRF2 localize to one of its two binding interfaces with KEAP1, an E3 ubiquitin ligase that promotes proteasome-dependent degradation of NRF2. Somatic mutations in KEAP1 occur commonly in human cancer, where KEAP1 may function as a tumor suppressor. These mutations distribute throughout the KEAP1 protein but little is known about their functional impact. In this study, we characterized 18 KEAP1 mutations defined in a lung squamous cell carcinoma tumor set. Four mutations behaved as wild-type KEAP1, thus are likely passenger events. R554Q, W544C, N469fs, P318fs, and G333C mutations attenuated binding and suppression of NRF2 activity. The remaining mutations exhibited hypomorphic suppression of NRF2, binding both NRF2 and CUL3. Proteomic analysis revealed that the R320Q, R470C, G423V, D422N, G186R, S243C, and V155F mutations augmented the binding of KEAP1 and NRF2. Intriguingly, these "super-binder" mutants exhibited reduced degradation of NRF2. Cell-based and in vitro biochemical analyses demonstrated that despite its inability to suppress NRF2 activity, the R320Q "superbinder" mutant maintained the ability to ubiquitinate NRF2. These data strengthen the genetic interactions between KEAP1 and NRF2 in cancer and provide new insight into KEAP1 mechanics. Cancer Res; 74(3); 808–17. 2013 AACR.