Distinct Binding Preferences between Ras and Raf Family Members and the Impact on Oncogenic Ras Signaling
Distinct Binding Preferences between Ras and Raf Family Members and the Impact on Oncogenic Ras Signaling
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DOI：
10.1016/j.molcel.2019.09.004
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发表时间：
2019-12-19
期刊：
影响因子：
16
通讯作者：
Morrison, Deborah K.
中科院分区：
文献类型：
--
作者：
Terrell, Elizabeth M.;Durrant, David E.;Morrison, Deborah K.
Ras GTP酶在人类癌症中经常发生突变，尽管Raf激酶是Ras信号传导的重要效应子，但特定Ras-Raf复合物的致瘤特性尚未得到很好的表征。在这里，我们研究了单个Ras和Raf蛋白在活细胞中使用生物发光共振能量转移（BRET）技术相互作用的能力。我们发现C-Raf以高亲和力结合所有突变型Ras蛋白，而B-Raf对突变型K-Ras表现出惊人的偏好。这种选择性是由B-Raf的酸性N-末端片段介导的，并且需要K-Ras多元区域进行高亲和力结合。此外，我们发现C-Raf对于突变体H-Ras驱动的信号传导是至关重要的，并且稳定B-Raf/C-Raf二聚化的事件，例如Raf抑制剂治疗或某些B-Raf突变，可以允许突变体H-Ras以增加的亲和力接合B-Raf以促进肿瘤发生，从而揭示了C-Raf在增强B-Raf功能中的先前未被认识的作用。
The Ras GTPases are frequently mutated in human cancer, and, although the Raf kinases are essential effectors of Ras signaling, the tumorigenic properties of specific Ras-Raf complexes are not well characterized. Here, we examine the ability of individual Ras and Raf proteins to interact in live cells using bioluminescence resonance energy transfer (BRET) technology. We find that C-Raf binds all mutant Ras proteins with high affinity, whereas B-Raf exhibits a striking preference for mutant K-Ras. This selectivity is mediated by the acidic, N-terminal segment of B-Raf and requires the K-Ras polybasic region for high-affinity binding. In addition, we find that C-Raf is critical for mutant H-Ras-driven signaling and that events stabilizing B-Raf/C-Raf dimerization, such as Raf inhibitor treatment or certain B-Raf mutations, can allow mutant H-Ras to engage B-Raf with increased affinity to promote tumorigenesis, thus revealing a previously unappreciated role for C-Raf in potentiating B-Raf function.