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: 8439585
• 负责人: Paul K Herman
• 金额: $ 28.88万
• 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/8439585
• 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）：我们对真核细胞在条件不利于持续生长时进入的G0样静息状态的生物学感兴趣。我们的目标是确定在这些静止期诱导的过程，并确定它们如何共同促进细胞存活。这个建议扩展了这种分析，并检查了一种特殊的核糖核蛋白（RNP）复合物，该复合物形成于静息细胞的细胞质中，称为加工体或P体。P体是相对较大的聚集体结构，其含有非翻译mRNA和一组不同的蛋白质组分，包括参与这些转录物加工的许多酶。有趣的是，P体只是在G0细胞中形成的大量类似细胞质结构之一。这种普遍性表明，这些复合物是重要的生物学的休息细胞，但目前知之甚少的基本原因，这种大规模的隔离的大分子。这些细胞质结构似乎对人类健康也很重要，因为相关的RNP复合物，即应激颗粒，与神经系统疾病的病理学有关，如肌萎缩性侧索硬化症（ALS）和脊髓小脑共济失调2型。总之，这些数据表明，这些细胞质灶在真核生物学中发挥着重要而多样的作用。因此，我们必须更好地了解这些结构的功能及其组装的调节方式。 这个建议解决了这些更广泛的问题，通过检查模型RNP复合物，酵母，酿酒酵母的P-体。从酵母到人类，P体都是保守的，我们对这些RNP结构的了解大部分来自对这种萌芽酵母的研究。然而，尽管进行了大量的努力，很少有人知道的机制，调节P体组装和生理作用的较大的病灶，形成在静止细胞。我们最近的工作对这两个问题提出了有趣的答案。特别地，我们已经鉴定了cAMP依赖性蛋白激酶（PKA）作为P体组装的关键调节剂，并且发现较大的P体病灶似乎是静止细胞长期存活所需的。我们的数据表明，PKA直接磷酸化Pat 1，一个保守的核心组成的P-体，从而破坏了形成的较大的聚集体结构。这里提出的实验旨在定义PKA控制的机制细节，并阐明更大的病灶如何促进细胞活力。最后，我们将进一步探索有趣的观察，信号分子，如PKA本身，也发现在P体和相关的复合物。待检验的基本假设是，随后恢复生长所需的特异性蛋白质和mRNA储存在静止细胞中的P体病灶内并受到保护。该建议的具体目的是：（1）确定PKA信号在P体灶形成的调节中的作用;（2）确定P体灶在静止细胞中的生理作用。