Regulatory mechanisms of the Hsp90 chaperone machinery

项目摘要 分子伴侣热休克蛋白-90（Hsp 90）对于蛋白质的折叠和 参与信号转导途径的一系列“客户”蛋白的活性。他们是 也导致许多疾病，包括癌症，神经退行性疾病，自身免疫性疾病， 和炎症性疾病。Hsp 90抑制策略目前正在探索中。 这些疾病的临床前研究和临床试验，然而， Hsp 90靶向治疗仍然未知。这部分是由于我们有限的 Hsp 90在细胞中的调控。解析详细的监管机制 Hsp 90在细胞中的功能可以提供新的策略，以增加细胞的效力， Hsp 90抑制剂。Hsp 90分子伴侣的功能与其ATP酶活性相结合， 由共分子伴侣和翻译后修饰（PTM）调节。但据 目前尚不清楚这些调节成分如何共同作用以微调Hsp 90的功能， 也有助于药物敏感性。在过去的五年里，我们取得了重大进展。 有助于理解Hsp 90通过辅助分子伴侣的调节， PTM。i）新的共分子伴侣：我们已经鉴定了三种新的共分子伴侣，FNIP 1，2 （统称为FNIP）和Tsc 1，它们减慢伴侣循环并促进伴侣- 激酶和非激酶客户端的连接。它们受PTM（磷酸化酶- 作用、O-GlcNAc酰化、SUMO化和泛素化）。它们的表达也增强了 Hsp 90与药物结合，从而使细胞对Hsp 90抑制剂敏感。（二）员额 热休克蛋白90的翻译修饰：我们在过去十年中对热休克蛋白90翻译修饰的研究 重新定义了其伴侣活性的调节，并揭示了相互调节， 客户端蛋白质，辅分子伴侣，和热休克蛋白90之间的存储机制。我们最近 显示TSC 1共伴侣蛋白的缺失导致Hsp 90的低乙酰化和Hsp 90的升高， ATP酶活性。随后它也降低了Hsp 90与其抑制剂的结合。我们 长期的目标是阐明Hsp 90分子伴侣调节的分子机制， 细胞和调节因子增强Hsp 90抑制剂的细胞效力。我们的战略 是使用生物化学，生物物理和细胞为基础的分析，以破译的相互联系， 辅助分子伴侣和PTM之间的相互作用和补偿机制。我们的愿景是 利用这些信息来剖析复杂的调控信号网络， 微调Hsp 90功能及其对细胞对Hsp 90敏感性的影响 tors.

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.