Cytoplasmic dyneins are motor proteins in the AAA+ superfamily that transport cellular cargos toward microtubule minus-ends. Recently, ciliobrevins were reported as selective cell-permeable inhibitors of cytoplasmic dyneins. As is often true for first-in-class inhibitors, the use of ciliobrevins has in part been limited by low potency. Moreover, suboptimal chemical properties, such as the potential to isomerize, have hindered efforts to improve ciliobrevins. Here, we characterized the structure of ciliobrevins and designed conformationally constrained isosteres. These studies identified dynapyrazoles, inhibitors more potent than ciliobrevins. At single-digit micromolar concentrations dynapyrazoles block intraflagellar transport in the cilium and lysosome motility in the cytoplasm, processes that depend on cytoplasmic dyneins. Further, we find that while ciliobrevins inhibit both dynein's microtubule-stimulated and basal ATPase activity, dynapyrazoles strongly block only microtubule-stimulated activity. Together, our studies suggest that chemical-structure-based analyses can lead to inhibitors with improved properties and distinct modes of inhibition.
细胞质动力蛋白是 AAA+ 超家族中的运动蛋白,可将细胞货物运往微管负端。最近有报道称,纤毛虫素是细胞质动力蛋白的选择性细胞渗透抑制剂。与第一类抑制剂通常的情况一样,纤毛虫素的使用在一定程度上受到了低效力的限制。此外,化学性质不理想(如可能发生异构化)也阻碍了纤毛虫素的改进。在这里,我们对纤毛虫素的结构进行了表征,并设计出了构象受限的异构体。这些研究发现了比纤毛虫素更有效的抑制剂 dynapyrazoles。在个位数微摩尔浓度下,dynapyrazoles 可阻断纤毛器中的纤毛内运输和细胞质中的溶酶体运动,而这些过程都依赖于细胞质中的动力蛋白。此外,我们还发现,纤毛虫素能抑制动力蛋白的微管刺激活性和基础 ATPase 活性,而达拉吡唑只能强烈阻断微管刺激活性。总之,我们的研究表明,基于化学结构的分析可以产生具有更好特性和不同抑制模式的抑制剂。