A comprehensive and functional analysis of B-Raf signalling

Ras/Raf/MEK/ERK信号通路在各种细胞过程和人类疾病中起着重要作用。丝氨酸/苏氨酸激酶B-Raf代表了人类癌症中的主要ERK激活剂和重要的癌蛋白。然而，对控制B-Raf的调控网络知之甚少。利用生物化学和遗传学方法，该项目的一部分将建立一个时空目录的已知和新的蛋白质-蛋白质相互作用和磷酸化事件发生在B-Raf信号体。Raf激活的关键调节步骤是Ras诱导的激活环磷酸化（TVKS基序）。令人惊讶的是，虽然Ras/Raf相互作用对ERK激活的重要性在十多年前就被发现了，但使TVKS基序磷酸化的激酶仍在等待其鉴定。因此，这种激酶在我们的ERK信号通路图上代表一个“白色点”，并可能为抑制（B-）Raf提供新的策略。因此，拟议研究的一个主要目的是首先识别并表征该激酶在体外和体内的生物学作用。这些研究还将通过分析TVKS磷酸化位点对体内B-Raf功能和恶性转化的重要性来补充。

The Ras/Raf/MEK/ERK signalling pathway plays a fundamental role in various cellular processes and human disorders. The serine/threonine kinase B-Raf represents the major ERK activator and an important oncoprotein in human cancer. However, little is known about the regulatory network controlling B-Raf. Using biochemical and genetic methods, one part of the project will establish a spatio-temporal catalogue of known and novel protein-protein interactions and phosphorylation events occurring in the B-Raf signalosome. A key regulatory step in Raf activation is the Ras-induced phosphorylation of the activation loop (TVKS-motif). Surprisingly, while the importance of the Ras/Raf interaction for ERK activation was discovered more than a decade ago, the kinase phosphorylating the TVKS-motif still awaits its identification. Consequently, this kinase represents a “white spot” on our map of ERK signalling and might provide novel strategies for the inhibition of (B-)Raf. Hence, a major aim of the proposed research is to first identify and then to characterise the biological role of this kinase in vitro and in vivo. These studies will be also complemented by analysing the importance of the TVKS phosphorylation sites for B-Raf function in vivo and for malignant transformation.