The Candida albicans acetylome in fungal virulence

 描述(申请人提供)：赖氨酸乙酰化是蛋白质最显著的翻译后修饰(PTM)之一，已被认为在通过组蛋白修饰和染色质功能调节来调节基因表达中起关键作用。尽管在过去的几十年里，我们对赖氨酸乙酰转移酶(KATS)和赖氨酸脱乙酰酶(KDAC)的了解取得了令人印象深刻的进展，但可逆赖氨酸乙酰化在从癌症到感染性疾病的基本细胞过程中的作用仍然知之甚少。特别是，对单个KATS/KDACs成员的染色质和非染色质功能的剖析仍然是一个重大的科学挑战。例如，有令人信服的证据表明，蛋白质的赖氨酸乙酰化调节白色念珠菌等病原真菌的毒力，但其潜在机制在很大程度上仍未被探索。了解这些机制变得更加重要，因为白色念珠菌乙酰转移酶KATS的识别基序是真菌王国独有的，因此是抗真菌药物开发的有希望的靶点。这项研究的中心假设是，蛋白质乙酰化在控制白念珠菌的细胞生理和毒力方面起着关键作用。我们提出这一假设是基于我们的初步数据，表明赖氨酸乙酰化是白色念珠菌中丰富的PTM形式。此外，我们以前的工作已经涉及到白念珠菌Hat1，一种聚合的组蛋白赖氨酸乙酰化酶，参与DNA损伤修复、形态发生、生物膜形成、抗真菌耐药性和毒力。然而，其他几种赖氨酸乙酰转移酶在该生物体中的作用仍不清楚。我们的初步研究还涉及Lig4的两个特定赖氨酸残基(K654和K655)的乙酰化，Lig4是参与非同源末端连接(NHEJ)依赖的DNA修复和调控白念珠菌形态发生和毒力的重要蛋白质。此外，新的RNA-seq初步数据表明，Hat1在线粒体功能以及非编码RNA(NcRNA)的处理和调节中发挥重要作用。因此，我们联合应用的主要目的是鉴定和表征白念珠菌Hat1的组蛋白和非组蛋白靶基因，并研究其在线粒体功能调节中的模糊作用和在NHEJ DNA修复中的可能作用。在初步数据的指导下，我们希望通过追求以下三个特定目标来检验我们的中心假设并实现本应用的目标：1)识别和表征Hat1的组蛋白和非组蛋白(非染色质)靶标。2)探讨NHEJ DNA修复通路乙酰化在白念珠菌毒力调控中的可能作用。3)探讨Hat1在ncRNA加工中的作用。这项提议的回报预计将是巨大的，因为我们希望发现对白色念珠菌致病重要的关键细胞过程的新调节模式。

 DESCRIPTION (provided by applicant): Lysine acetylation is one of the most prominent post-translational modifications (PTM) of proteins and has been recognized to play a key role in regulation of gene expression by histone modification and modulation of chromatin function. Despite impressive advances in our understanding of lysine acetyltransferases (KATs) and lysine deacetylases (KDACs) during the last decades, the role of reversible lysine acetylation in fundamental cellular processes in physiology and pathology from cancer to infectious diseases still remains poorly understood. In particular, the dissection of chromatin and non-chromatin functions of individual KATs/KDACs members still represents a major scientific challenge. For example, there is compelling evidence that lysine acetylation of proteins modulates virulence of pathogenic fungi such as Candida albicans, but the underlying mechanisms have remained largely unexplored. Understanding these mechanisms is all the more important because the recognition motifs of C. albicans acetyltransferases KATs are unique to the fungal kingdom and thus represent promising targets for antifungal drug discovery. The central hypothesis of the proposed research is that protein acetylation plays pivotal roles in controlling the cellular physiology and virulence of C. albicans. We formulated this hypothesis based on our preliminary data indicating that lysine acetylation is an abundant form of PTM in C. albicans. Furthermore, our previous work has implicated C. albicans Hat1, a paradigmatic histone lysine acetylase, in DNA damage repair, morphogenesis, biofilm formation, antifungal drug resistance, and virulence. However, the roles of several other lysine acetyltransferase enzymes in this organism have remained unknown. Our preliminary studies have also implicated acetylation at two specific lysine residues (K654 and K655) of Lig4, an important protein involved in Non-Homologous End Joining (NHEJ)-dependent DNA repair and modulating morphogenesis and virulence of C. albicans. Furthermore, new preliminary RNA-seq data suggest that Hat1 has important roles in mitochondrial function, as well as in the processing and regulation of non-coding RNAs (ncRNA). The main objective in our joint application is therefore to identify and characterize the histone and non-histone target genes of C. albicans Hat1 and to investigate its ill-defined role in regulation of mitochondrial function and a possible role in the NHEJ DNA repair. Guided by the preliminary data, we expect to test our central hypothesis and to accomplish the objectives of this application by pursuing the following three Specific Aims: 1) To identify and characterize both histone and non- histone (non-chromatin) targets of Hat1. 2) To investigate the possible role of acetylation of the NHEJ DNA repair pathway in regulation of C. albicans virulence. 3) To investigate role of Hat1 in the processing of ncRNA. The payoffs of this proposal are expected to be significant because we expect to uncover novel modes of regulation of key cellular processes important for pathogenesis of C. albicans.