RAF是MAPK信号通路的核心成员，其突变会导致通路异常活化并诱发癌症。RAF蛋白家族包含相似结构域，但其分子调控机制却不尽相同。我们发现缺失羧基端尾巴（CT）会降低BRAF稳定性并提高其活性，但不影响其他RAF蛋白。通过序列分析，我们发现只有BRAF的CT含有CDC37结合基序，并验证了Hsp90-CDC37复合物与BRAF CT的相互作用。进一步分析BRAF缺失CT前后结合蛋白的差异，发现缺失CT可增强BRAF与FZR1的结合。我们推测BRAF CT通过与Hsp90-CDC37复合物结合维持稳定性，在失去其保护后通过FZR1介导的蛋白酶体降解。本课题拟通过分子生物学、生物化学等方法研究CT对BRAF稳定性和活性的独特分子调控机制，并利用Crispr对CT进行精准编辑降解BRAF，以期抑制含有BRAF V600E肿瘤细胞的生长，进而为新一代靶向BRAF突变的药物开发提供新的方向。

RAF family kinase is the key component of Ras/RAF/MEK/ERK (MAPK) signaling pathway, whose mutations result in the hyperactive MAPK pathway and lead to carcinogenesis and some genetic diseases. Although all RAFs have a similar structure and activate an identical downstream pathway of MEK-ERK, their activity per se is regulated through distinct mechanisms. We found that deletion of the C-terminal tail (CT) significantly disrupted the stability of BRAF and elevated its activity, but not affected CRAF or ARAF, which indicates that CT exclusively regulates the stability and activity of BRAF. By analyzing the sequences, we found a unique CDC37 binding motif within the CT of BRAF and validated the interaction of BRAF CT and CDC37. To explore the differences of binding partners between BRAF±CT, we utilized the quantitative mass spectrometry to analyze the protein complex from purified BRAF±CT and found that the depletion of CT significantly enhanced the binding affinity of BRAF and FZR1. Based on these results, we hypothesize that BRAF is stabilized by Hsp90-CDC37 complex and will be degraded by the proteasome via FZR1 when released from the Hsp90-CDC37 complex. We will also delete the CT of BRAF to inhibit the growth of tumors harboring BRAF V600E through Crispr-guided precise genome modification. Our goal is to evaluate the molecular mechanism of CT in regulating the stability and activity of BRAF employing bioinformatics, molecular biology, and biochemistry which will eventually provide both theoretical and practical knowledge for the development of novel therapeutic approaches targeting BRAF mutations.