An allosteric kinase inhibitor binds the p21-activated kinase autoregulatory domain covalently.
An allosteric kinase inhibitor binds the p21-activated kinase autoregulatory domain covalently.
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DOI：
10.1158/1535-7163.mct-09-0102
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发表时间：
2009-09
影响因子：
5.7
通讯作者：
Peterson JR
中科院分区：
文献类型：
--
作者：
Viaud J;Peterson JR
由于激酶在癌症中的频繁失调，激酶是肿瘤学中重要的治疗靶标。然而，典型的ATP竞争性激酶抑制剂也抑制可能导致药物毒性的脱靶激酶。别构抑制剂代表了实现更大激酶选择性的替代方法，尽管此类化合物的实例很少。在这里，我们阐明了IPA-3，一种Pak激酶激活的变构抑制剂的作用机制。我们证明，IPA-3共价结合到Pak 1的调节结构域，并防止结合到上游激活剂Cdc 42。然而，预活化的Pak 1既不被IPA-3显著抑制也不被IPA-3显著结合，表明相互作用的精致构象特异性。使用放射性标记的IPA-3，我们表明，抑制剂结合是特定的和可逆的还原环境。最后，使用IPA-3的细胞实验表明Pak 1参与了佛波酯刺激的膜皱褶。这项研究揭示了一种新的变构机制激酶抑制通过共价靶向的调节结构域。
Kinases are important therapeutic targets in oncology due to their frequent deregulation in cancer. Typical ATP-competitive kinase inhibitors, however, also inhibit off-target kinases that could lead to drug toxicity. Allosteric inhibitors represent an alternative approach to achieve greater kinase selectivity although examples of such compounds are few. Here we elucidate the mechanism of action of IPA-3, an allosteric inhibitor of Pak kinase activation. We demonstrate that IPA-3 binds covalently to the Pak1 regulatory domain and prevents binding to the upstream activator Cdc42. Pre-activated Pak1, however, is neither inhibited nor bound significantly by IPA-3, demonstrating exquisite conformational specificity of the interaction. Using radiolabeled IPA-3 we show that inhibitor binding is specific and reversible in reducing environments. Finally, cell experiments using IPA-3 implicate Pak1 in phorbol-ester stimulated membrane ruffling. This study reveals a novel allosteric mechanism for kinase inhibition through covalent targeting of a regulatory domain.