Mechanisms & Inhibition of Histone Acetyltransferases

描述（由申请人提供）本提案是GM 64327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/GCN 5的催化机制、调节和合成抑制剂。HAT被认为是通过催化组蛋白上关键赖氨酸残基的乙酰化来调节基因表达，从而重塑染色质。它们还被认为是多种转录因子和其他蛋白质乙酰化的催化剂。 虽然在过去的8年里，已经了解了很多关于HAT的分子克隆以来，我们仍然有很大的差距，在我们的理解的催化机制，调节和功能的HAT，包括生物医学上重要的p300/CBP和PCAF/GCN 5家庭。 有效的和选择性的细胞可渗透的HAT抑制剂尚未报道这些酶。这项建议的具体目标是：i）定义最近发现的“活化环”对p300 HAT的催化作用的机制作用，ii）阐明p300活化环和自乙酰化在介导蛋白质-蛋白质相互作用中的作用，iii）定义结构柔性环在PCAF/GCN 5的催化机制和底物选择性中的作用，和iv）开发有效的和选择性的细胞渗透性HAT抑制剂，并将其应用于解决HAT功能的生物学问题。对HAT的机制和调控的研究将拓宽我们对与基因表达相关的正常和病理生理过程的理解。HAT酶的选择性抑制剂可用于治疗癌症、HIV和与蛋白质乙酰化失调相关的其它疾病。

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.