Regulatory mechanisms of the Hsp90 chaperone machinery

项目总结 分子伴侣热休克蛋白-90(Hsp90)对折叠和 参与信号转导途径的一系列‘客户’蛋白的活性。他们是 也是许多疾病的罪魁祸首，包括癌症、神经退行性变、自身免疫 和炎症性疾病。目前正在探索HSP90抑制策略 这些疾病在临床前研究和临床试验中，然而最佳使用 HSP90靶向治疗仍不清楚。这在一定程度上是因为我们的 热休克蛋白90在细胞内的调控知识。拆解详细的监管机制 Hsp90在细胞中的功能的研究可以提供新的策略来提高细胞潜能 HSP90抑制剂。HSP90的伴侣功能与其ATPase活性相偶联，这是 受辅助伴侣和翻译后修饰(PTM)调节。然而，它是 不清楚这些监管组件如何协同工作来微调Hsp90功能和 也会增加对药物的敏感性。在过去的五年里，我们取得了重大进展 共同伴侣对理解Hsp90调控的贡献和 PTMS。一)新的辅助伴侣：我们确定了三个新的辅助伴侣，FNIP1、2 (统称为FNIP)和TSC1，它们减缓伴侣周期并促进伴侣- 激活型和非激动型客户端的连接。它们受PTMS(磷酸化- On、O-GlcN酰化、糖基化和泛素化)。它们的表达也增强了 热休克蛋白90与药物结合，从而使细胞对热休克蛋白90抑制剂敏感。Ii)邮寄- Hsp90的翻译修饰：我们过去十年在Hsp90 PTM方面的工作 重新定义了其伴侣活性的调节，并揭示了相互调节-- 客户蛋白、辅助伴侣和热休克蛋白90之间的相互作用机制。我们最近做了 研究表明，TSC1辅助伴侣的缺失会导致Hsp90的低乙酰化和升高 它的ATPase活性。随后，它还减少了Hsp90与其抑制剂的结合。我们的 长期目标是解开Hsp90伴侣调节的分子机制。 提高Hsp90抑制剂的细胞效力的细胞和调节因子。我们的战略 是使用生化、生物物理和基于细胞的分析来破译相互联系-- TY及其与PTMS之间的代偿机制。我们的愿景是 利用这些信息来剖析涉及到的复杂的监管信号网络 微调Hsp90功能及其对细胞对Hsp90抑制敏感性的影响 托尔斯。

PROJECT SUMMARY The molecular chaperone Heat Shock Protein-90 (Hsp90) is essential for the folding and activity of an array of `client' proteins involved in signal transduction pathways. They are also responsible for many maladies including cancer, neurodegenerative, autoimmune and inflammatory diseases. Hsp90 inhibition strategies are currently being explored in these diseases in pre-clinical studies and clinical trials, however the optimal use of Hsp90-targeted therapeutics remains unknown. This is partly due to our limited knowledge of Hsp90 regulation in cells. Unraveling the detailed regulatory mechanisms of Hsp90 function in cells can provide new strategies to increase the cellular potency of Hsp90 inhibitors. Hsp90 chaperone function is coupled to its ATPase activity, which is regulated by co-chaperones and posttranslational modifications (PTMs). However, it is unclear how these regulatory components work together to fine tune Hsp90 function and also contribute towards drug sensitivity. During the past five years we have made major contributions towards the understanding of Hsp90 regulation by co-chaperones and PTMs. i) New co-chaperones: We have identified three new co-chaperones, FNIP1, 2 (collectively FNIPs) and Tsc1, that decelerate the chaperone cycle and facilitate chaper- oning of both kinase and non-kinase clients. They are regulated by PTMs (phosphoryla- tion, O-GlcNAcylation, SUMOlyation and ubiquitination). Their expression also enhances Hsp90 binding to drugs and consequently sensitizes cells to Hsp90 inhibitors. ii) Post- translational modification of Hsp90: Our work during the past decade on Hsp90 PTMs has redefined the regulation of its chaperone activity and revealed the reciprocal regula- tory mechanisms between client proteins, co-chaperones, and Hsp90. We have recently shown that loss of TSC1 co-chaperone leads to hypoacetylation of Hsp90 and elevated its ATPase activity. It also subsequently decreased Hsp90 binding to its inhibitors. Our long-term goal is to unravel the molecular mechanism of Hsp90 chaperone regulation in cells and regulatory factors enhancing cellular potency of Hsp90 inhibitors. Our strategy is to use biochemical, biophysical and cell-based assays to decipher the interconnectivi- ty and compensatory mechanisms between the co-chaperones and PTMs. Our vision is to utilize this information to dissect the intricate network of regulatory signals involved in fine tuning Hsp90 function and their impact towards cellular sensitivity to Hsp90 inhibi- tors.