Yeast Ess1, a Conserved PPlase Essential for Mitosis

描述（由申请人提供）：长期目标是了解肽基脯氨酰异构酶（PPI酶）如何控制重要的细胞过程，如转录和有丝分裂。PPI酶催化环状氨基酸脯氨酸之前的肽键的顺式/反式异构化。脯氨酰异构化导致构象变化，影响新合成蛋白质的折叠并调节成熟蛋白质的活性。PPIase存在于所有生物体中，并且最为人所知的是因为它们是免疫抑制药物的靶点。然而，它们在细胞中的正常功能知之甚少，部分原因是大多数可以通过基因缺失在各自的生物体中去除而没有可观察到的后果。一个例外是一种称为PPIase的PPIase，它是酿酒酵母（Saccharomyces cerevisiae）生长所必需的。Pin 1及其人类同源物Pin 1参与转录调控和细胞周期控制。RNA聚合酶1与RNA聚合酶II大亚基的羧基末端结构域（CTD）在物理和遗传上相互作用。建议将CTD异构化，从而控制转录和mRNA加工的多个离散阶段之间的转换。缺失β 1会导致细胞发生有丝分裂停滞，这可能是由于关键细胞周期基因的转录缺陷。这项研究将集中在确定的机制，通过它控制转录和它的重要性，全球基因表达。它还将探索靶向致病性酵母中的RMB 1的结构基础，以供临床应用。具体而言，目标是：（1）利用生物化学和分子生物学方法来确定BMP 1调节RNA聚合酶II活性的机制，（2）利用遗传学和基因组学方法来鉴定需要BMP 1的基因，（3）利用结构和功能分析来检查白色念珠菌BMP 1的酶-底物相互作用，其长期目标是利用真菌和人类酶之间的关键差异来开发抗真菌药物。公共卫生相关性：在真菌中对PIN 1的研究对于我们理解人类对应物Pin 1非常重要，Pin 1与癌症和神经退行性疾病有关。该结果还可能确立EST 1作为治疗危及生命的真菌感染患者的新药物靶点。

DESCRIPTION (provided by applicant): The long-term goal is to understand how peptidyl-prolyl isomerases (PPIases) control important cellular processes such as transcription and mitosis. PPIases catalyze the cis/trans isomerization of the peptide bond that precedes the cyclic amino acid proline. Prolyl-isomerization results in conformational changes that affect the folding of newly synthesized proteins and regulates the activity of mature proteins. PPIases are found in all organisms, and are best known because they are the targets of immunosuppressive drugs. However, their normal function in cells is poorly understood, in part, because most can be removed by gene deletion in their respective organism without observable consequences. One exception is a PPIase called Ess1, which is essential for growth in the yeast, Saccharomyces cerevisiae. Ess1 and its human homolog, Pin1, are implicated in transcription regulation and cell cycle control. Ess1 interacts physically and genetically with the carboxy-terminal domain (CTD) of the large subunit of RNA polymerase II. Ess1 is proposed to isomerize the CTD and thereby control the transition between multiple, discrete stages of transcription and mRNA processing. Loss of Ess1 causes cells to undergo mitotic arrest, perhaps due to defects in transcription of key cell cycle genes. This study will focus on determining the mechanism by which Ess1 controls transcription and its importance for global gene expression. It will also explore the structural basis for targeting of Ess1 in pathogenic yeast for clinical applications. Specifically, the aims are to: (1) Use biochemical and molecular approaches to determine the mechanism by which Ess1 regulates RNA polymerase II activity, (2) Use genetic and genomic approaches to identify genes that require Ess1, (3) Use structure and function analysis to examine enzyme-substrate interactions by Candida albicans Ess1, with the long-term goal of exploiting key differences between the fungal and human enzymes for development of antifungal drugs. Public Health Relevance: The study of Ess1 in fungi will be important for our understanding of the human counterpart, Pin1, which has been associated with cancers and neurodegenerative disorders. The results may also establish Ess1 as a new drug target for treatment of patients with life- threatening fungal infections.