Hallmarks of Molecular Action of Microtubule Stabilizing Agents EFFECTS OF EPOTHILONE B, IXABEPILONE, PELORUSIDE A, AND LAULIMALIDE ON MICROTUBULE CONFORMATION
Hallmarks of Molecular Action of Microtubule Stabilizing Agents EFFECTS OF EPOTHILONE B, IXABEPILONE, PELORUSIDE A, AND LAULIMALIDE ON MICROTUBULE CONFORMATION
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DOI：
10.1074/jbc.m110.162214
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发表时间：
2011-04-01
影响因子：
4.8
通讯作者：
Xiao, Hui
中科院分区：
文献类型：
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作者：
Khrapunovich-Baine, Marina;Menon, Vilas;Xiao, Hui
微管稳定剂（MSAs）包括一类结合微管（MT）聚合物并稳定其不被分解的药物。其中一些药物目前作为抗癌药物在临床使用，而其他药物则处于不同的开发阶段。尽管如此，对其作用的分子模式还没有足够的了解。本实验室最近利用氢-氘交换结合质谱（MS）的研究为紫杉醇和迪德molide对鸡红细胞（CET）微管的构象影响提供了新的信息。我们在此报告了一项综合分析，研究了艾替龙B、伊沙匹龙（IXEMPRA (TM)）、劳莱莫胺和佩洛西苷a对CET构象的影响。我们的比较氢-氘交换质谱研究结果表明，所有msa对α -微管蛋白的c端H12螺旋有显著的构象影响，这可能是先前观察到的MT与微管相关蛋白和运动蛋白相互作用调节的分子机制。更重要的是，msa稳定MT的主要模式是紧致相邻α - β -微管蛋白异源二聚体之间在二聚体界面上的纵向相互作用。与先前报道的牛脑微管蛋白的观察结果相反，在CET中相邻原丝之间的横向相互作用被peloruside A和laulimalide（在紫杉烷位点外结合的药物）特别强烈地稳定下来。这不仅突出了微管蛋白同型组成在调节药物对MT构象和稳定性的影响中的重要性，而且还为紫杉烷和替代位点结合药物联合使用时观察到的协同作用提供了潜在的解释。
Microtubule stabilizing agents (MSAs) comprise a class of drugs that bind to microtubule (MT) polymers and stabilize them against disassembly. Several of these agents are currently in clinical use as anticancer drugs, whereas others are in various stages of development. Nonetheless, there is insufficient knowledge about the molecular modes of their action. Recent studies from our laboratory utilizing hydrogen-deuterium exchange in combination with mass spectrometry (MS) provide new information on the conformational effects of Taxol and discodermolide on microtubules isolated from chicken erythrocytes (CET). We report here a comprehensive analysis of the effects of epothilone B, ixabepilone (IXEMPRA (TM)), laulimalide, and peloruside A on CET conformation. The results of our comparative hydrogen-deuterium exchange MS studies indicate that all MSAs have significant conformational effects on the C-terminal H12 helix of alpha-tubulin, which is a likely molecular mechanism for the previously observed modulations of MT interactions with microtubule-associated and motor proteins. More importantly, the major mode of MT stabilization by MSAs is the tightening of the longitudinal interactions between two adjacent alpha beta-tubulin heterodimers at the interdimer interface. In contrast to previous observations reported with bovine brain tubulin, the lateral interactions between the adjacent protofilaments in CET are particularly strongly stabilized by peloruside A and laulimalide, drugs that bind outside the taxane site. This not only highlights the significance of tubulin isotype composition in modulating drug effects on MT conformation and stability but also provides a potential explanation for the synergy observed when combinations of taxane and alternative site binding drugs are used.