Covalent modification of Cys-239 in -tubulin by small molecules as a strategy to promote tubulin heterodimer degradation
Covalent modification of Cys-239 in -tubulin by small molecules as a strategy to promote tubulin heterodimer degradation
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小分子对 β-微管蛋白中 Cys-239 的共价修饰作为促进微管蛋白异二聚体降解的策略
DOI：
10.1074/jbc.ra118.006325
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发表时间：
2019-05-17
影响因子：
4.8
通讯作者：
Chen, Lijuan
中科院分区：
文献类型：
--
作者：
Yang, Jianhong;Li, Yong;Chen, Lijuan
临床微管靶向药物在功能上分为微管不稳定剂和微管稳定剂。这两类药物通过结合微管蛋白上的不同位点，抑制或促进聚合来实现微管抑制，而对微管蛋白异源二聚体的蛋白水平没有伴随影响。在这里，我们已经确定了一系列具有不同结构的小分子，可能代表第三类新型微管蛋白抑制剂，它们通过与β-微管蛋白的Cys-239共价结合来促进降解。本研究重点研究的小分子包括T0070907（一种过氧化物酶体增殖物激活受体γ抑制剂）、T007-1（一种T0070907衍生物）、T138067、N,N ' -乙烯-双（碘乙酰胺）（EBI）和异硫氰酸烯丙酯（AITC）。无标记定量蛋白质组学分析显示，T007-1以高选择性促进微管蛋白降解。质谱分析结果显示T0070907和T007-01与β-微管蛋白的Cys-239共价结合。此外，T007-1对含有Cys-239 （β2、β4和β5）的微管蛋白亚型有降解作用，但对含有Ser-239 （β3、β6）或含有C239S取代的突变型β-微管蛋白不起降解作用。据报道，三种小分子（T138067、EBI和AITC）也能与β-微管蛋白的Cys-239共价结合，类似地诱导微管蛋白降解。我们的研究结果强烈表明，小分子对β-微管蛋白的Cys-239进行共价修饰可能是一种促进微管蛋白异源二聚体降解的新策略。我们认为这些小分子代表了第三类新型微管蛋白抑制剂，它们通过降解活性发挥作用。
Clinical microtubule-targeting drugs are functionally divided into microtubule-destabilizing and microtubule-stabilizing agents. Drugs from both classes achieve microtubule inhibition by binding different sites on tubulin and inhibiting or promoting polymerization with no concomitant effects on the protein levels of tubulin heterodimers. Here, we have identified a series of small molecules with diverse structures potentially representing a third class of novel tubulin inhibitors that promote degradation by covalent binding to Cys-239 of β-tubulin. The small molecules highlighted in this study include T0070907 (a peroxisome proliferator-activated receptor γ inhibitor), T007-1 (a T0070907 derivative), T138067, N,N′-ethylene-bis(iodoacetamide) (EBI), and allyl isothiocyanate (AITC). Label-free quantitative proteomic analysis revealed that T007-1 promotes tubulin degradation with high selectivity. Mass spectrometry findings showed covalent binding of both T0070907 and T007-01 to Cys-239 of β-tubulin. Furthermore, T007-1 exerted a degradative effect on tubulin isoforms possessing Cys-239 (β2, β4, and β5(β)) but not those containing Ser-239 (β3, β6) or mutant β-tubulin with a C239S substitution. Three small molecules (T138067, EBI, and AITC) also reported to bind covalently to Cys-239 of β-tubulin similarly induced tubulin degradation. Our results strongly suggest that covalent modification of Cys-239 of β-tubulin by small molecules could serve as a novel strategy to promote tubulin heterodimer degradation. We propose that these small molecules represent a third novel class of tubulin inhibitor agents that exert their effects through degradation activity.