The roles of the Polo and MAP kinase signalling in driving polarised growth in fission yeast

Polo 和 MAP 激酶信号在驱动裂殖酵母极化生长中的作用

• 批准号: BB/E002056/1
• 负责人: Janni Petersen
• 金额: $ 47.97万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FE002056%2F1
• 关键词: roles; Polo; MAP; kinase; signalling

During the development of specialized cell types within an organism, diversity is generated in part by polarised growth and intracellular asymmetry. This relies on the polarised distribution of cell-fate determinants, through interplay between elements of the cytoskeleton. The cytoskeleton is an 'internal scaffold' that is important for controlling many aspects of cell function, including the ability of dividing cells to inherit different components. Such 'asymmetric' divisions are important in setting up the diversity of different cells within the body. The two cytoskeletal elements studied in this project, actin and microtubules, are highly dynamic polymers that grow and shrink rapidly to respond to external and internal cues, in order to establish and maintain a polarised cytoskeleton. The fission yeast is an ideal model system for studying polarised growth because it is a simple cell type. Its microtubules and actin interact in the same way as they do in more complex systems. The combined effect of the actin and microtubule cytoskeletons strictly limits growth to the cell ends of this cylindrical shaped cell. Furthermore the underlying controls responsible for changes in cytoskeletal polarisation are identical or highly reminiscent of those of higher systems. Polo kinases are regulatory molecules that have previously been linked to the control of cell division but not to control during the non-dividing phases of the cell cycle known as interphase. Therefore, our recent finding that polo kinases controls interphase cell growth by regulating the cytoskeleton has identified a novel signaling pathway important for cytoskeletal polarisation. We aim to further characterize this interphase role of the fission yeast polo kinase Plo1. We know that the ability of Plo1 to control the cytoskeleton is controlled by the stress response pathway (SRP). SRPs enable cells to rapidly respond to a variety of changes in their environment including excessive heat and starvation. Organisms such as humans have several SRPs, each of which responds to different stresses. In contrast in fission yeast a single SRP responds to a variety of external stimuli, making this yeast a particularly attractive model to provide guidance for the study of the more complex human SRPs. This project aim to study how cells recover from stress induced perturbations of growth. In doing this it will extend our understanding of how actin and microtubule cytoskeletons talk to each other to initiate new growth. We will take advantage of the ease with which specific mutations can be used to study the function of a protein in yeast. We will first ask whether the ability of the polo kinase to physically modify target molecules is important for the effects we see or whether it simply has to be present (i.e. has a purely structural role). The second aim is to catalogue the changes in Plo1/SRP localization within the cells that accompany cell cycle and stress induced changes in the cytoskeleton. By generating fusions between both SRP components and Plo1 and fluorescent proteins we have been able to see where in living cells the molecules go. This allows us to observe the changes in the distribution of the proteins within the cells as the cells are exposed to different external conditions. The third aim is to identify and characterize the mechanism by which Polo and SRP signaling are coordinated to regulate changes in cytoskeletal polarisation through the identification and characterization of targets/interactors of the SRP and Polo signaling pathways. In summary this project will increase our understanding of how cells respond to signals from the environment to regulate and maintain cell growth.

在生物体内特定细胞类型的发展过程中，生物多样性的产生部分是由于极化生长和细胞内的不对称性。这依赖于细胞命运决定因素的极化分布，通过细胞骨架元素之间的相互作用。细胞骨架是一个“内部支架”，对控制细胞功能的许多方面都很重要，包括分裂细胞继承不同成分的能力。这种不对称的分裂对人体内不同细胞的多样性很重要。这个项目中研究的两种细胞骨架元素--肌动蛋白和微管--是高度动态的聚合物，它们可以迅速生长和收缩，对外部和内部的提示做出反应，以建立和维持极化的细胞骨架。分裂酵母是研究极化生长的理想模型系统，因为它是一种简单的细胞类型。它的微管和肌动蛋白的相互作用方式与它们在更复杂的系统中的作用方式相同。肌动蛋白和微管细胞骨架的联合作用严格限制了这种圆柱形细胞的细胞末端的生长。此外，导致细胞骨架极化变化的潜在控制与更高级系统的控制相同或高度相似。Polo激酶是一种调节分子，以前被认为与细胞分裂的控制有关，但在被称为间期的细胞周期的非分裂阶段中没有控制作用。因此，我们最近发现，Polo激酶通过调节细胞骨架来控制间期细胞的生长，这发现了一条对细胞骨架极化很重要的新的信号通路。我们的目标是进一步表征分裂酵母Polo激酶Plo1的这种间期作用。我们知道，Plo1控制细胞骨架的能力是由应激反应途径(SRP)控制的。SRP使细胞能够迅速对环境中的各种变化做出反应，包括过热和饥饿。像人类这样的生物体有几个SRP，每个SRP对不同的压力做出反应。相比之下，在分裂酵母中，单个SRP对各种外部刺激做出反应，使这种酵母成为一个特别有吸引力的模型，为研究更复杂的人类SRP提供指导。本项目旨在研究细胞如何从应激诱导的生长扰动中恢复。通过这样做，它将扩展我们对肌动蛋白和微管细胞骨架如何相互对话以启动新的生长的理解。我们将利用特定突变可以轻松地用于研究酵母中蛋白质的功能。我们首先会问，Polo激酶物理修饰目标分子的能力对我们所看到的效果是重要的，还是它只是必须存在(即具有纯粹的结构作用)。第二个目的是分类Plo1/SRP在细胞内定位的变化，这些变化伴随着细胞周期和应激诱导的细胞骨架的变化。通过在SRP组分和Plo1和荧光蛋白之间产生融合，我们已经能够看到活细胞中分子的去向。这使我们能够观察到当细胞暴露在不同的外部条件下时，细胞内蛋白质分布的变化。第三个目标是通过识别和表征SRP和Polo信号通路的靶点/相互作用，识别和表征Polo和SRP信号通路协调调节细胞骨架极化变化的机制。总而言之，这个项目将增加我们对细胞如何响应来自环境的信号以调节和维持细胞生长的理解。

项目成果

Control of Sty1 MAPK activity through stabilisation of the Pyp2 MAPK phosphatase.

通过稳定 Pyp2 MAPK 磷酸酶来控制 Sty1 MAPK 活性。

• DOI: 10.1242/jcs.122531
• 发表时间: 2013
• 期刊: Journal of cell science
• 影响因子: 4
• 作者: Kowalczyk KM