Mechanisms & Inhibition of Histone Acetyltransferases

描述(由申请人提供)本提案是GM64327的竞争性续展申请，涉及两个组蛋白乙酰转移酶(HAT)家族p300/CBP和PCAF/GCN5的催化机制、调节和合成抑制剂。HATS被认为是通过催化组蛋白上关键赖氨酸残基的乙酰化来通过染色质重塑来调节基因表达的。它们还被认为是各种转录因子和其他蛋白质乙酰化的催化剂。尽管在过去的8年里，关于HATS的分子克隆已经取得了很大的进展，但对于HATS的催化机制、调控和功能，包括具有重要生物医学意义的p300/CBP和PCAF/GCN5家族，我们的理解仍然存在很大差距。 对于这些酶，还没有报道有效的和选择性的细胞通透性HAT抑制剂。这一建议的具体目的是：1)确定最近发现的‘激活环’对p300 HAT催化作用的机制作用；2)阐明p300激活环和自乙酰化在调节蛋白质-蛋白质相互作用中的作用；3)确定结构灵活的环在PCAF/GCN5的催化机制和底物选择性中的作用；4)开发有效和选择性的细胞通透性HAT抑制剂，并将它们应用于解决HAT功能的生物学问题。对HATS机制和调控的研究将有助于我们更好地理解与基因表达相关的正常和病理生理过程。HAT酶的选择性抑制剂可能在治疗癌症、艾滋病毒和其他与蛋白质乙酰化失调有关的疾病方面有用。

DESCRIPTION (provided by applicant) This proposal is a competing renewal application of GM64327 that concerns the catalytic mechanisms, regulation, and synthetic inhibitors of two histone acetyltransferase (HAT) families p300/CBP and PCAF/GCN5. HATs are proposed to regulate gene expression via chromatin remodelling by catalyzing acetylation of key lysine residues on histones. They are also thought to serve as catalysts for the acetylation of a variety of transcription factors and other proteins. Although much has been learned in the past 8 years about HATs since their molecular cloning, there are still large gaps in our understanding about the catalytic mechanisms, regulation, and functions of HATs including the biomedically important p300/CBP and PCAF/GCN5 families. Potent and selective cell permeable HAT inhibitors have yet to be reported for these enzymes. The specific aims of this proposal are: i) define the mechanistic role of the recently discovered 'activation loop' on the catalytic action of p300 HAT, ii) clarify the effects of the p300 activation loop and autoacetylation in mediating protein-protein interactions, iii) define the role of a structurally flexible loop in the catalytic mechanism and substrate selectivity of PCAF/GCN5, and iv) develop potent and selective cell permeable HAT inhibitors and apply them to address biological questions of HAT function. The studies on mechanism and regulation of HATs should lead to a broadening of our understanding of normal and pathophysiologic processes related to gene expression. Selective inhibitors of HAT enzymes may be useful in the treatment of cancer, HIV, and other diseases related to the dysregulation of protein acetylation.