WDR23 regulates NRF2 independently of KEAP1.
WDR23 regulates NRF2 independently of KEAP1.
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DOI：
10.1371/journal.pgen.1006762
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发表时间：
2017-04
期刊：
影响因子：
4.5
通讯作者：
Curran SP
中科院分区：
文献类型：
--
作者：
Lo JY;Spatola BN;Curran SP
细胞对压力的适应对于确保生物体的生存至关重要。NRF 2/NFE 2L 2是异生物质应激反应的关键决定因素，并且KEAP 1-CUL 3蛋白酶体系统的负调节的丧失与几种化疗和放射抗性癌症有关。有利地使用C.在线虫和人类细胞培养模型中，我们建立了一个新的WDR 23-DDB 1-CUL 4调节轴，用于NRF 2活性，其独立于经典的KEAP 1-CUL 3系统。WDR 23结合NRF 2的Neh 2结构域内的DIDLID序列以调节其稳定性;这种调节不依赖于KEAP 1结合DLG或ETGE基序。WDR 23的C-末端结构域是高度保守的，并且参与DDB 1-CUL 4复合物对NRF 2的调节。WDR 23的加入增加了细胞对细胞毒性化疗药物的敏感性，并抑制了KEAP 1阴性癌细胞系中的NRF 2。总之，我们的研究结果确定WDR 23作为NRF 2蛋白质稳态的替代调节剂，并揭示了一种独立于KEAP 1调节NRF 2活性和细胞保护能力的细胞途径。在整个生命中长期暴露于环境压力（“麻烦”）与人类的几种癌症有关。细胞对压力的适应对于确保生物体的生存至关重要，而NRF 2是细胞压力反应的一个研究非常充分的关键决定因素，在癌症生物学和对外源性物质（包括化疗）的反应中发挥着复杂的作用。我们的研究已经确定了WDR 23作为Cullin 4（CUL 4）-DDB 1 E3-泛素连接酶的底物受体的功能和进化保守的作用，所述Cullin 4（CUL 4）-DDB 1 E3-泛素连接酶调节NRF 2蛋白水平和活性，并且独立于经典的KEAP 1-CUL 3途径而操作。KEAP 1一直是NRF 2的最高度研究的调节因子，因为在许多侵袭性癌症中发现了KEAP 1的突变，其导致NRF 2的不受控制的激活和化学抗性。重要的是，KEAP 1（-/-）癌细胞中WDR 23表达的增加恢复了异常的NRF 2调节。在缺乏KEAP 1样系统的情况下，C.已显示线虫WDR-23调节蠕虫细胞保护性转录因子SKN-1。我们使用C。通过线虫遗传学方法鉴定NRF 2对哺乳动物细胞保护的保守调节机制。总的来说，我们的研究表明NRF 2稳态的控制比以前认识到的要复杂得多。
Cellular adaptation to stress is essential to ensure organismal survival. NRF2/NFE2L2 is a key determinant of xenobiotic stress responses, and loss of negative regulation by the KEAP1-CUL3 proteasome system is implicated in several chemo- and radiation-resistant cancers. Advantageously using C. elegans alongside human cell culture models, we establish a new WDR23-DDB1-CUL4 regulatory axis for NRF2 activity that operates independently of the canonical KEAP1-CUL3 system. WDR23 binds the DIDLID sequence within the Neh2 domain of NRF2 to regulate its stability; this regulation is not dependent on the KEAP1-binding DLG or ETGE motifs. The C-terminal domain of WDR23 is highly conserved and involved in regulation of NRF2 by the DDB1-CUL4 complex. The addition of WDR23 increases cellular sensitivity to cytotoxic chemotherapeutic drugs and suppresses NRF2 in KEAP1-negative cancer cell lines. Together, our results identify WDR23 as an alternative regulator of NRF2 proteostasis and uncover a cellular pathway that regulates NRF2 activity and capacity for cytoprotection independently of KEAP1. Chronic exposure to environmental stressors throughout life (“the exposome”) has been tied to several cancers in humans. Cellular adaptation to stress is essential to ensure organismal survival, and NRF2 is an exceptionally well-studied and key determinant of cellular stress responses that plays complex roles in cancer biology and responses to xenobiotics, including chemotherapies. Our studies have established a functional and evolutionarily conserved role for WDR23 as a substrate receptor for the Cullin4(CUL4)-DDB1 E3-ubiquitin ligase, which regulates NRF2 protein levels and activity, and which operates independently of the canonical KEAP1-CUL3 pathway. KEAP1 has been the most highly studied regulator of NRF2, as mutations in KEAP1, which result in uncontrolled activation of NRF2 and chemo-resistance, are found in many aggressive cancers. Importantly, increased expression of WDR23 in KEAP1(-/-) cancer cells restores aberrant NRF2 regulation. In the absence of a KEAP1-like system, C. elegans WDR-23 has been shown to regulate the worm cytoprotective transcription factor SKN-1. We have leveraged C. elegans genetic approaches to identify conserved regulatory mechanisms of mammalian cytoprotection by NRF2. Collectively, our studies suggest control of NRF2 homeostasis is much more sophisticated than previously appreciated.