Academic cross-fertilization by public screening yields a remarkable class of protein phosphatase methylesterase-1 inhibitors
Academic cross-fertilization by public screening yields a remarkable class of protein phosphatase methylesterase-1 inhibitors
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DOI：
10.1073/pnas.1015248108
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发表时间：
2011-04-26
影响因子：
11.1
通讯作者：
Cravatt, Benjamin F.
中科院分区：
文献类型：
--
作者：
Bachovchin, Daniel A.;Mohr, Justin T.;Cravatt, Benjamin F.
美国国立卫生研究院（NIH）资助的筛选中心为学术研究人员提供了一个特殊的机会，使其能够针对蛋白质靶点寻找小分子探针，这些靶点要么是制药行业当前不感兴趣的，要么是超出其所用标准技术范围的。在此，我们描述了针对一个此类靶点——蛋白质磷酸酶甲基酯酶 - 1（PME - 1）进行抑制剂筛选的结果。PME - 1调节蛋白质磷酸酶2A（PP2A）的甲基酯化状态，并与癌症和神经退行性疾病有关。PME - 1的抑制剂尚未见报道，我们认为这至少部分是由于缺乏与高通量筛选兼容的底物检测方法。我们表明，通过基于荧光偏振 - 活性的蛋白质谱分析（fluopol - ABPP）可以对PME - 1进行检测，并利用该平台对拥有30万多种化合物的NIH小分子文库进行了筛选。这次筛选确定了一类不同寻常的化合物——氮杂 - β - 内酰胺（ABL），它是一种强效（半数抑制浓度值约为10纳摩尔）的共价PME - 1抑制剂。有趣的是，ABL并非来自商业供应商，而是学术界对公共文库的贡献。我们通过竞争性ABPP表明，ABL在活细胞和小鼠中对PME - 1具有极高的选择性，在这些细胞和小鼠中，酶的失活导致去甲基化的PP2A大幅减少。总之，我们结合了先进的合成方法和化学蛋白质组学方法，发现了一类ABL抑制剂，可用于选择性地干扰不同生物系统中PME - 1的活性。更广泛地说，这些结果说明了公共筛选中心如何能够成为枢纽，为对具有挑战性的蛋白质靶点创建一流的药理探针感兴趣的合成化学实验室和化学生物学实验室创造自发的合作机会。
National Institutes of Health (NIH)-sponsored screening centers provide academic researchers with a special opportunity to pursue small-molecule probes for protein targets that are outside the current interest of, or beyond the standard technologies employed by, the pharmaceutical industry. Here, we describe the outcome of an inhibitor screen for one such target, the enzyme protein phosphatase methylesterase-1 (PME-1), which regulates the methylesterification state of protein phosphatase 2A (PP2A) and is implicated in cancer and neurodegeneration. Inhibitors of PME-1 have not yet been described, which we attribute, at least in part, to a dearth of substrate assays compatible with high-throughput screening. We show that PME-1 is assayable by fluorescence polarization-activity-based protein profiling (fluopol-ABPP) and use this platform to screen the 300,000+ member NIH small-molecule library. This screen identified an unusual class of compounds, the aza-beta-lactams (ABLs), as potent (IC(50) values of approximately 10 nM), covalent PME-1 inhibitors. Interestingly, ABLs did not derive from a commercial vendor but rather an academic contribution to the public library. We show using competitive-ABPP that ABLs are exquisitely selective for PME-1 in living cells and mice, where enzyme inactivation leads to substantial reductions in demethylated PP2A. In summary, we have combined advanced synthetic and chemoproteomic methods to discover a class of ABL inhibitors that can be used to selectively perturb PME-1 activity in diverse biological systems. More generally, these results illustrate how public screening centers can serve as hubs to create spontaneous collaborative opportunities between synthetic chemistry and chemical biology labs interested in creating first-in-class pharmacological probes for challenging protein targets.