Signaling iteractions in cytokinesis, cell wall biogenesis, and growth in fungi

描述(申请人提供)：本申请的科学目标是：1-了解肌球蛋白II在胞质分裂、细胞壁生物发生和细胞生长中连接功能的信号相互作用2-了解肌球蛋白II功能和细胞壁完整性之间的关系，以及3-确定抗真菌药物的新潜在靶点。我们将通过确定哪些代谢过程受到肌动非依赖性和肌动球蛋白非依赖性突变对胞质分裂的影响，哪些信号通路是细胞在这些条件下生存所必需的信号通路，以及在这些基因突变中连接这些通路的生化成分来实现这一点。肌球蛋白11缺失的酿酒酵母细胞(Myola)表现出多种表型，既具有胞质分裂的特征，又具有细胞壁突变的特征。为了确定这些表型是否与基因表达的变化有关，我们测定了Myol A菌株的整体转录图谱。这些研究证实，依赖于PKC1的信号通路在这些菌株中协同激活了细胞壁应激基因的转录。核糖体蛋白基因的协同下调也发生了，并观察到核糖体蛋白基因RPL30和RPS31的过度表达部分恢复了Myol A菌株的细胞壁功能。我们的主要假设是，Myol A菌株中细胞壁应激基因的转录激活和核糖体蛋白基因的下调分别代表了细胞壁和胞质分裂突变的不同表型；每种突变都采用了相互关联的不同的基本信号通路。为了验证这一假设，我们的具体目标是：1-进行胞质分裂突变株chs2A和细胞壁突变株fks1 A的mRNA转录分析，以便随后与Myola菌株进行比较；2-进行胞质分裂突变株中mRNA翻译调控的分析；3-确定PKC1、TOR1和TOR2信号通路在细胞质分裂突变株中的地位并测试它们对细胞活性的要求；以及4-识别胞质分裂和细胞壁突变株中PKC1和TOR信号通路的共同调节因子。这项研究的意义在于发现了真菌细胞中协调肌动蛋白功能和细胞壁生物发生的新的调控联系。这项拟议的研究还将增加我们对肌球蛋白II丢失如何对酵母细胞的应激反应做出贡献的理解。了解肌球蛋白II和应激信号之间的相互作用可以帮助识别新的抗真菌药物的潜在靶点。

DESCRIPTION (provided by applicant): The scientific goals of this application are to 1- understand signaling interactions connecting myosin II functions in cytokinesis, cell wall biogenesis, and cell growth 2- understand the relation between myosin II function and cell wall integrity and 3- identify new potential targets for antifungal drugs. We will accomplish this by identifying what metabolic processes are affected by the interruption of cytokinesis by actomyosindependent and actomyosin-independent mutations, what signaling pathways are necessary for cell survival under these conditions, and the biochemical components linking these pathways in these genetic mutants. Myosin ll-deficient Saccharomyces cerevisiae cells (myolA) exhibit multiple phenotypes with characteristics of both cytokinesis and cell wall mutants. To determine if these phenotypes were related to changes in gene expression, we determined the global transcription profile of myol A strains. These studies corroborated that the PKC1-dependent signaling pathway coordinately activates the transcription of cell wall stress genes in these strains. Coordinated down-regulation of ribosomal protein genes also occurs and it was observed that over expression of ribosomal protein genes RPL30 and RPS31 partially restored cell wall function in a myol A strain. Our main hypothesis is that transcriptional activation of cell wall stress genes and the down-regulation of ribosomal protein genes in myol A strains represent separate phenotypes for cell wall and cytokinesis mutants, respectively; each employing distinct essential signaling pathways that are interconnected. To test this hypothesis our specific aims are to: 1- conduct mRNA transcription analysis of the cytokinesis mutant chs2A and the cell wall mutant fksl A for subsequent comparison with myolA strains, 2-conduct analysis of mRNA translational regulation in cytokinesis mutants, 3- determine the status of the PKC1, TOR1, and TOR2 signaling pathways in cytokinesis mutant strains and test their requirement for cell viability, and 4- identify common regulators of the PKC1 and TOR signaling pathways in cytokinesis and cell wall mutants. The significance of this study lies in the discovery of new regulatory connections that coordinate actomyosin function and cell wall biogenesis in fungal cells. The proposed study will also increase our understanding about how loss of myosin II contributes to the stress response in yeast cells. Knowledge of the interaction between myosin II and stress signaling can lead to identification of potential targets for new antifungal drugs.