Molecular Mechanism of Inhibition of the Human Protein Complex Hsp90-Cdc37, a Kinome Chaperone-Cochaperone, by Triterpene Celastrol
Molecular Mechanism of Inhibition of the Human Protein Complex Hsp90-Cdc37, a Kinome Chaperone-Cochaperone, by Triterpene Celastrol
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DOI：
10.1002/anie.200900929
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发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Schwalbe, Harald
中科院分区：
文献类型：
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作者：
Sreeramulu, Sridhar;Gande, Santosh Lakshmi;Schwalbe, Harald
激酶组伴侣蛋白Hsp 90（激酶组=生物体中所有蛋白激酶的集合）的ATP酶活性的抑制长期以来被认为是抗癌治疗的分子靶标。Cdc 37是哺乳动物细胞中Hsp 90的辅助分子伴侣，靶向蛋白激酶，并在各种癌症中上调。[1，2]蛋白质-蛋白质复合物的KD值为1.2 μm，被认为通过稳定恶性细胞中的各种不同致癌激酶来介导致癌作用。然而，Cdc 37和Hsp 90也可以单独起作用，至少在酵母中是这样。干扰Cdc 37或Hsp 90或破坏Hsp 90-Cdc 37复合物的低分子量分子最近被提议作为一类新的抗癌剂。[3，4]基于基因的表达研究已经鉴定了三萜雷公藤红素，其代表了一类新的Hsp 90的非ATP竞争性抑制剂。[5]在胰腺细胞系和对接实验中的免疫沉淀表明，雷公藤红素发挥其抗增殖活性结合到热休克蛋白90（热休克蛋白90 N）的N-末端结构域，从而破坏热休克蛋白90 N和Cdc 37之间的复合物。[6]在体内，雷公藤红素表现出显着抑制肿瘤生长的裸鼠与前列腺癌或胰腺癌。[6，7]在此，我们详细描述了雷公藤红素如何破坏人Hsp 90-Cdc 37复合物。1H，15 N-HSQC NMR实验通过化学位移扰动（CSP）检测配体与靶标的结合。[8-10]我们研究了雷公藤红素对1H，15 N-标记的Hsp 90 N（23 kDa）与未标记的全长Cdc 37（45 kDa）的复合物的影响（图1A）。由于复合物中蛋白质的横向弛豫速率增加（约为1.5%），70 kDa），HSQC谱
Inhibition of the ATPase activity of the kinome chaperone Hsp90 (kinome= set of all protein kinases in an organism) has long been known as molecular target for anticancer therapy. Cdc37, a cochaperone of Hsp90 in mammalian cells, targets protein kinases and is upregulated in various cancers.[1, 2] The protein–protein complex forms with a KD value of 1.2 μm and is considered to mediate carcinogenesis by stabilizing a variety of different oncogenic kinases in malignant cells. However, Cdc37 as well as Hsp90 can also act alone, at least in yeast. Low-molecular-weight molecules that interfere with Cdc37 or Hsp90 or disrupt the Hsp90–Cdc37 complex have recently been proposed as a new class of anticancer agents.[3, 4] Gene-based expression studies have identified the triterpene celastrol, which represents a new class of non ATP-competitive inhibitors of Hsp90.[5] Immunoprecipitation in a pancreatic cell line and docking experiments suggested that celastrol exerts its antiproliferative activity by binding to the N-terminal domain of Hsp90 (Hsp90N), thereby disrupting the complex between Hsp90N and Cdc37.[6] In vivo, celastrol showed significant inhibition of tumor growth in nude mice with prostate or pancreatic cancer.[6, 7]Herein, we describe in detail how celastrol disrupts the human Hsp90–Cdc37 complex. 1H, 15N-HSQC NMR experiments detect ligand binding to a target through chemical-shift perturbations (CSPs).[8–10] We investigated the effects of celastrol on the complex of 1H, 15N-labeled Hsp90N (23 kDa) with unlabeled full-length Cdc37 (45 kDa)(Figure 1A). As a result of the increased transverse relaxation rates of the protein in complex (approx. 70 kDa), the HSQC spectrum of