Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Department of Cancer Biology , Dana-Farber Cancer Institute , Boston , Massachusetts 02115 , United States.
Chemical Biology and Therapeutics , Novartis Institutes for BioMedical Research , 4056 Basel , Switzerland.
ACS Chem Biol. 2019 Apr 19;14(4):587-593. doi: 10.1021/acschembio.8b00722. Epub 2019 Mar 11.
The oncogenic V617F mutation lies in the pseudokinase domain of JAK2, marking it as a potential target for development of compounds that might inhibit the pathogenic activity of the mutant protein. We used differential scanning fluorimetry to identify compounds that bind the JAK2 pseudokinase domain. Crystal structures of five candidate compounds with the wild-type domain reveal their modes of binding. Exploration of analogs of screening hit BI-D1870 led to the identification of compound 2, a 123 nM ligand for the pseudokinase domain. Interestingly, crystal structures of the V617F domain in complex with two unrelated compounds reveal a conformation that is characteristic of the wild-type domain, rather than that previously observed for the V617F mutant. These structures suggest that certain ATP-site ligands can modulate the V617F allosteric site, thereby providing a mechanistic rationale for targeting the pseudokinase domain and a structural foundation for development of more potent and pseudokinase-selective compounds.
致癌 V617F 突变位于 JAK2 的假激酶结构域，这使其成为可能开发抑制突变蛋白致病活性的化合物的潜在目标。我们使用差示扫描荧光法来鉴定与 JAK2 假激酶结构域结合的化合物。与野生型结构域的五种候选化合物的晶体结构揭示了它们的结合模式。对筛选出的 BI-D1870 类似物的探索导致了化合物 2 的鉴定，这是一种对假激酶结构域具有 123 nM 亲和力的配体。有趣的是，与两种不相关的化合物结合的 V617F 结构域的晶体结构揭示了一种特征为野生型结构域的构象，而不是先前观察到的 V617F 突变体的构象。这些结构表明，某些 ATP 结合位点配体可以调节 V617F 的变构位点，从而为靶向假激酶结构域提供了一种机制上的理由，并为开发更有效和假激酶选择性的化合物提供了结构基础。
