The regulation and function of cytoplasmic foci in quiescent cells

静止细胞胞质灶的调控和功能

• 批准号: 8598912
• 负责人: Paul K Herman
• 金额: $ 29.02万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8598912
• 关键词: Address; Affect; Amyotrophic Lateral Sclerosis; Biological; Biological Process; Biology; Cell Survival; Cells; Cellular biology; Complex; Cyclic AMP-Dependent Protein Kinases; Cytoplasm; Cytoplasmic Granules; Cytoplasmic Structures; Data; Developmental Biology; Enzymes; Eukaryota; Eukaryotic Cell; Glean; Goals; Growth; Health; Human; Interphase Cell; Knowledge; Light; Messenger RNA; Modeling; Pathology; Phase; Phosphorylation; Physiological; Play; Prevalence; Process; Protein Kinase; Proteins; Regulation; Rest; Ribonucleoproteins; Role; Saccharomyces cerevisiae; Saccharomycetales; Set protein; Signal Transduction; Signaling Molecule; Stress; Structure; Testing; Transcript; Type 2 Spinocerebellar Ataxia; Work; Yeasts; human disease; insight; interest; macromolecule; nervous system disorder; novel; protein aggregate; public health relevance; research study; stem

DESCRIPTION (provided by applicant): We are interested in the biology of the G0-like resting states that eukaryotic cells enter when conditions are not conducive to continued growth. Our goal is to define the processes that are induced during these periods of quiescence and to determine how they collectively contribute to cell survival. This proposal extends this analysis and examines a particular ribonucleoprotein (RNP) complex that forms in the cytoplasm of resting cells, known as a Processing-body, or P-body. P-bodies are relatively large aggregate structures that contain non-translating mRNAs and a distinct set of protein constituents, including a number of enzymes involved in the processing of these transcripts. Interestingly, the P-body is just one of a large number of similar cytoplasmic structures that form in the G0 cell. This prevalence suggests that these complexes are important for the biology of the resting cell, but little is presently known about the underlying reasons for this large-scale sequestration of macromolecules. These cytoplasmic structures also appear to be important for human health as a related RNP complex, the stress granule, has been implicated in the pathology of neurological disorders, like amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia type 2. In all, thes data suggest that these cytoplasmic foci play important and diverse roles in eukaryotic biology. It is therefore critical that we develop a better understanding of the functions of these structure and the manner in which their assembly is regulated. This proposal addresses these broader issues by examining a model RNP complex, the P-body of the yeast, Saccharomyces cerevisiae. P-bodies have been conserved from yeast to humans, and much of what we know about these RNP structures has come from studies with this budding yeast. However, despite extensive effort, little was known about the mechanisms regulating P-body assembly and the physiological role of the larger foci that form in quiescent cells. Our recent work has suggested interesting answers to both of these questions. In particular, we have identified the cAMP-dependent protein kinase (PKA) as a key regulator of P- body assembly, and found that the larger P-body foci appear to be required for the long-term survival of quiescent cells. Our data indicate that PKA directly phosphorylates Pat1, a conserved core constituent of P- bodies, and thereby disrupts the formation of the larger aggregate structures. The experiments proposed here aim to define the mechanistic details of this control by PKA and to elucidate how the larger foci promote cell viability. Finally, we will explore further the intriguing observation that signaing molecules, like PKA itself, are also found in P-bodies and related complexes. The underlying hypothesis to be tested is that specific proteins and mRNAs required for the subsequent resumption of growth are stored and protected within P-body foci in quiescent cells. The specific aims of this proposal are: (1) to determine the role of PKA signaling in the regulation of P-body foci formation; and (2) to determine the physiological role of P-body foci in quiescent cells.

描述（由申请人提供）：我们对类似G0的休息状态的生物学感兴趣，即在条件不利于持续生长的情况下进入真核细胞。我们的目标是定义在这些静止期间诱导的过程，并确定它们如何共同促进细胞存活。该建议扩展了此分析，并检查了在静息细胞的细胞质中形成的特定核糖核蛋白（RNP）复合物（称为加工体或P体）。 P体是相对较大的聚集体结构，其中包含非翻译mRNA和一组不同的蛋白质成分，包括涉及这些转录本处理的许多酶。有趣的是，P体只是G0细胞中形成的大量类似的细胞质结构之一。这种流行率表明，这些复合物对于静息细胞的生物学很重要，但目前对大规模隔离大分子的根本原因知之甚少。作为相关的RNP复合物，应激颗粒，这些细胞质结构似乎对人类健康很重要，与神经系统疾病的病理有关，例如氨基营养性的侧面硬化症（ALS）和脊髓骨叶性共济失调2型2类。总体而言，这些细胞群的数据表明，这些细胞局部局灶性娱乐性和多样性均具有e e。因此，至关重要的是，我们对这些结构的功能以及调节其组装的方式有更好的理解。 该提案通过检查模型RNP复合物，酵母菌的P体，葡萄糖酿酒酵母来解决这些更广泛的问题。 p-体从酵母到人类一直保存，我们对这些RNP结构的了解大部分来自这种萌芽的酵母菌的研究。然而，尽管付出了很大的努力，但对调节P体组装的机制以及在静止细胞中形成的较大焦点的生理作用知之甚少。我们最近的工作提出了这两个问题的有趣答案。特别是，我们已经将依赖CAMP的蛋白激酶（PKA）确定为P-体组装的关键调节剂，并发现静态细胞长期存活似乎是必需的较大的P体灶。我们的数据表明，PKA直接磷酸化PAT1，PAT1是P PAT1的核心组成部分，从而破坏了较大的聚集体结构的形成。此处提出的实验旨在定义PKA控制的机械细节，并阐明较大的焦点如何促进细胞活力。最后，我们将进一步探讨一个有趣的观察结果，即在P体和相关复合物中也发现了像PKA本身这样的签名分子。要测试的基本假设是，随后恢复生长所需的特定蛋白质和mRNA在静态细胞中被储存和保护。该提案的具体目的是：（1）确定PKA信号在调节P体型形成中的作用； （2）确定P体灶在静态细胞中的生理作用。