Lamin A biogenesis, processing and progeria

核纤层蛋白 A 的生物发生、加工和早衰

• 批准号: 7912046
• 负责人: Susan D. Michaelis
• 金额: $ 32.51万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2012-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7912046
• 关键词: Abnormal Cell; Acute; Address; Adverse effects; Aging; Aging-Related Process; Architecture; Area; Binding Proteins; Biochemical; Biogenesis; Biological; Biological Process; Biology; C-terminal; Cardiomyopathies; Cell Line; Cell Nucleus; Cells; Characteristics; Cleaved cell; Cysteine; Data; Detection; Disease; Dysplasia; Electron Microscopy; Enzymes; Event; Exhibits; Face; Failure; Farnesyl Transferase Inhibitor; Figs - dietary; Gene Targeting; Genes; Genetic; Genetic Transcription; Gold; HIV therapy; In Vitro; Knowledge; Label; Laboratories; Lamin Type A; Lamin Type B; Lead; Light; Link; Lipodystrophy; Location; Mammalian Cell; Maps; Measures; Mediating; Membrane; Metabolic; Metalloproteases; Methylation; Methyltransferase; Modeling; Modification; Molecular; Morphology; Muscular Dystrophies; Mutation; Nuclear; Nuclear Envelope; Nuclear Inner Membrane; Nuclear Localization Signal; Pathology; Pathway interactions; Physiologic pulse; Physiological; Play; Post-Translational Protein Processing; Premature aging syndrome; Process; Progeria; Proteins; Proteolysis; Research; Role; Series; Site; Structural Protein; Syndrome; Tail; Testing; Therapeutic; Toxic effect; Ursidae Family; Work; Yeasts; Zinc; base; disease phenotype; farnesylation; inhibitor/antagonist; insight; interest; lamin B receptor; normal aging; novel; prelamin A; prenylation; public health relevance; research study

DESCRIPTION (provided by applicant): This project focuses on the biogenesis of Lamin A, a critical structural component of the nuclear envelope. Surprisingly, recent studies have revealed that mutations in the gene encoding Lamin A result in a wide range of diseases called the "laminopathies" (encompassing cardiomyopathy, muscular dystrophy, lipodystrophy, and progeroid disorders), leading to a resurgence of interest in the biology of Lamin A. The Lamin A precursor, prelamin A, undergoes a series of post-translational processing events, including: 1) C- terminal CaaX modification (prenylation, proteolysis, and carboxyl methylation), followed by 2) an endoproteolytic cleavage event, mediated by the zinc metalloprotease ZmpSte24, that removes the CaaX- modified C-terminus to yield mature Lamin A. In previous years of this project, our laboratory discovered ZmpSte24 as a key enzyme in the biogenesis of yeast a-factor. From these findings this project has evolved to study the biogenesis of Lamin A in mammalian cells. The most severe laminopathy is the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS). Strikingly, there appears to be a direct link between defective Zmpste24-mediated endoproteolytic processing of prelamin A and progeroid diseases based on the findings that: 1) HGPS results from a mutation in which the ZmpSte24 cleavage site within Lamin A is deleted, and 2) the progeroid disorders mandibuloacral dysplasia (MAD) and restrictive dermopathy (RD) map to ZmpSte24. Thus, it appears that the persistently prenylated form of Lamin A that is present in HGPS or zmpste24-/- cells leads to accelerated aging pathologies. In this proposal we will define key cell biological aspects of Lamin A processing and address the role that a lack of processing plays in disease mechanisms. We will use molecular, cell biological, genetic, and biochemical approaches to address the following aims: Aim 1) determine the cellular location of Lamin A processing (nucleoplasmic vs. the cytosolic face of the ER); Aim 2) determine the fate of the cleaved C- terminal tail; Aim 3) determine the recognition sequences within prelamin A important for ZmpSte24 cleavage, and define how Zmpste24 cleaves prelamin A using purified enzyme; and Aim 4) investigate the molecular mechanisms by which failure to cleave the prelamin A tail leads to cellular and disease phenotypes. In particular we will test whether methylation may contribute to the toxicity of Lamin A in HGPS. The intriguing finding that progeroid diseases are caused by incomplete processing of prelamin A has underscored the importance of a comprehensive understanding of the entire processing pathway, which we address in this proposal. Our studies will provide insight into therapeutic options for progeroid disorders. The significance of this research is heightened by recent findings that inhibition of ZmpSte24-mediated processing of prelamin A may contribute to HIV therapy-induced side effects, and possibly to the mechanisms of normal aging. PUBLIC HEALTH RELEVANCE: Mutations in the nuclear structural protein Lamin A cause the premature aging disorder Hutchinson-Gilford Progeria Syndrome (HGPS) and a spectrum of diseases known as "laminopathies". This project addresses fundamental unanswered questions about Lamin A biology, including how it is processed within the cell and how abnormal processing can cause disease, as in HGPS. Our studies will provide insight into potential therapeutic options for premature aging disorders, and may also shed light on the mechanisms underlying the normal aging process.

描述（由申请人提供）：该项目重点关注核纤层蛋白 A 的生物发生，核纤层蛋白 A 是核膜的关键结构成分。令人惊讶的是，最近的研究表明，编码核纤层蛋白 A 的基因突变会导致多种称为“核纤层蛋白病”（包括心肌病、肌肉萎缩症、脂肪营养不良和早衰症）的疾病，从而重新引起人们对核纤层蛋白 A 生物学的兴趣。 Lamin A。 Lamin A 前体，prelamin A，经历一系列翻译后加工事件，包括： 1) C 端 CaaX 修饰（异戊二烯化、蛋白水解和羧基甲基化），然后是 2) 由锌金属蛋白酶 ZmpSte24 介导的内切蛋白水解裂解事件，该事件去除 CaaX 修饰的 C 末端以产生成熟的核纤层蛋白 A。在该项目的前几年，我们的实验室发现 ZmpSte24 是酵母 a 因子生物合成中的关键酶。根据这些发现，该项目已发展到研究哺乳动物细胞中核纤层蛋白 A 的生物发生。最严重的椎板病是早衰症哈钦森-吉尔福德早衰综合症（HGPS）。引人注目的是，基于以下发现，Zmpste24 介导的前核纤层蛋白 A 的内切蛋白水解加工缺陷与早衰性疾病之间似乎存在直接联系：1) HGPS 是由核纤层蛋白 A 内的 ZmpSte24 切割位点被删除的突变引起的，2)早衰症下颌骨发育不良 (MAD) 和限制性皮肤病 (RD) 映射到 ZmpSte24。因此，HGPS 或 zmpste24-/- 细胞中存在的持续异戊二烯化形式的核纤层蛋白 A 似乎会导致加速衰老病理。在本提案中，我们将定义核纤层蛋白 A 加工的关键细胞生物学方面，并解决缺乏加工在疾病机制中所起的作用。我们将使用分子、细胞生物学、遗传和生化方法来实现以下目标： 目标 1) 确定核纤层蛋白 A 加工的细胞位置（内质网的核质与胞质面）；目标 2) 确定切割的 C 末端尾部的命运；目标 3) 确定 prelamin A 内对 ZmpSte24 裂解重要的识别序列，并定义 Zmpste24 如何使用纯化的酶裂解 prelamin A；目标 4) 研究前核纤层蛋白 A 尾部切割失败导致细胞和疾病表型的分子机制。我们将特别测试甲基化是否会导致 HGPS 中核纤层蛋白 A 的毒性。早衰性疾病是由前核纤蛋白 A 的不完全加工引起的这一有趣的发现强调了全面了解整个加工途径的重要性，我们在本提案中对此进行了阐述。我们的研究将深入了解早衰症的治疗选择。最近的发现强调了这项研究的重要性，即抑制 ZmpSte24 介导的 prelamin A 加工可能会导致 HIV 治疗引起的副作用，并可能导致正常衰老的机制。 公共健康相关性：核结构蛋白核纤层蛋白 A 的突变会导致早衰症哈钦森-吉尔福德早衰综合症 (HGPS) 和一系列称为“核纤层蛋白病”的疾病。该项目解决了有关核纤层蛋白 A 生物学的基本未解答问题，包括它在细胞内如何加工以及异常加工如何导致疾病，如 HGPS。我们的研究将深入了解早衰性疾病的潜在治疗选择，也可能揭示正常衰老过程的机制。