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）：该项目的重点是lamin A的生物发生，这是核包膜的关键结构成分。 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翻译后处理事件，包括：1）C-终末CAAX修饰（原质化，蛋白水解和羧基甲基化），然后是2）2）一个内蛋白溶解裂解事件，由锌金属蛋白酶ZMPSTE24介导，从而消除了Cax-Modified C- Termerinus fiervered C- Termerinus A.在此期间，这是在这种情况下进行的。 ZMPSTE24作为酵母A因子生物发生的关键酶。从这些发现中，该项目已演变为研究哺乳动物细胞中层蛋白A的生物发生。最严重的椎板病是Hutchinson-Gilford综合征（HGPS）的过早衰老疾病。 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皮肤病（RD）映射到ZMPSTE24。因此，似乎存在于HGPS或ZMPSTE24 - / - 细胞中的lamin A的持续原型化形式导致加速衰老的病理。在此提案中，我们将定义层粘连蛋白A处理的关键细胞生物学方面，并解决缺乏加工在疾病机制中所发挥的作用。我们将使用分子，细胞生物学，遗传和生化方法来解决以下目的：目标1）确定层粘连蛋白A加工的细胞位置（核质和ER的胞质面）；目标2）确定切割的c-末端尾巴的命运； AIM 3）确定预胺内的识别序列对于ZMPSTE24裂解很重要，并使用纯化的酶来定义ZMPSTE24如何切割预裂解前A；目标4）研究未能裂解前尾能导致细胞和疾病表型的分子机制。特别是我们将测试甲基化是否可能有助于HGP中层粘连蛋白A的毒性。令人着迷的发现，即前代疾病是由预胺A的不完整处理引起的，这强调了对整个加工途径的全面理解的重要性，我们在本提案中解决了这一问题。我们的研究将提供对孕激素疾病治疗选择的见解。最近发现，抑制ZMPSTE24介导的预胺A的加工可能有助于HIV治疗引起的副作用，并可能有可能促进正常衰老的机制，从而提高了这项研究的意义。 公共卫生相关性：核结构蛋白层固定蛋白A的突变导致过早衰老疾病Hutchinson-Gilford progeria综合征（HGP）和一系列被称为“椎板病”的疾病。该项目解决了有关层固定生物学的基本未解决的问题，包括在细胞内处理方式以及异常处理可能引起疾病，如HGP中。我们的研究将洞悉过早衰老疾病的潜在治疗选择，并可能阐明正常衰老过程的机制。