The molecular chaperone heat shock protein 90 (Hsp90) has an essential but largely undefined role in maintaining proteostasis in Plasmodium falciparum, the most lethal malaria parasite. Herein, we identify BX-2819 and XL888 as potent P. falciparum (Pf)Hsp90 inhibitors. Derivatization of XL888’s scaffold led to the development of Tropane 1, as a PfHsp90-selective binder with nanomolar affinity. Hsp90 inhibitors exhibit anti-Plasmodium activity against the liver, asexual blood, and early gametocyte life stages. Thermal proteome profiling was implemented to assess PfHsp90-dependent proteome stability, and the proteasome—the main site of cellular protein recycling—was enriched among proteins with perturbed stability upon PfHsp90 inhibition. Subsequent biochemical and cellular studies suggest that PfHsp90 directly promotes proteasome hydrolysis by chaperoning the active 26S complex. These findings expand our knowledge of the PfHsp90-dependent proteome and protein quality control mechanisms in these pathogenic parasites, as well as further characterize this chaperone as a potential antimalarial drug target.

分子伴侣热休克蛋白 90 (Hsp90) 在维持恶性疟原虫（最致命的疟疾寄生虫）的蛋白质稳态方面具有重要但很大程度上不确定的作用。在此，我们将 BX-2819 和 XL888 鉴定为有效的恶性疟原虫(Pf)Hsp90 抑制剂。 XL888 支架的衍生化导致 Tropane 1的开发，作为具有纳摩尔亲和力的 PfHsp90 选择性结合剂。 Hsp90 抑制剂对肝脏、无性血液和早期配子体生命阶段表现出抗疟原虫活性。通过热蛋白质组分析来评估 PfHsp90 依赖性蛋白质组稳定性，并且蛋白酶体（细胞蛋白质回收的主要位点）在 PfHsp90 抑制后稳定性受到干扰的蛋白质中富集。随后的生化和细胞研究表明，PfHsp90 通过陪伴活性 26S 复合物直接促进蛋白酶体水解。这些发现扩展了我们对这些致病寄生虫中 PfHsp90 依赖性蛋白质组和蛋白质质量控​​制机制的了解，并进一步将这种伴侣描述为潜在的抗疟药物靶点。