Phospholipase-Mediated Stress Response in Fission Yeast

裂殖酵母中磷脂酶介导的应激反应

• 批准号: 6872509
• 负责人: STEVAN MARCUS
• 金额: $ 29.09万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6872509
• 关键词: Schizosaccharomyces pombe; adenylate cyclase; biological signal transduction; cell cycle; cell growth regulation; cell osmotic pressure; cyclic AMP; enzyme mechanism; fungal genetics; fungal proteins; gene mutation; growth media; lysophospholipase; microorganism growth; protein localization; stress

DESCRIPTION (provided by applicant): Phospholipase B (PLB) enzymes comprise what is perhaps the most poorly understood class of phospholipases in terms of biological functions. Although several PLB isozymes have been identified in genetically tractable yeasts, their physiological functions are largely unknown. We have elucidated a role for a newly identified member of the fungal PLB family, Plbl, as an essential mediator of osmotic stress response in the fission yeast, Schizosaccharomyces pombe, plb 1delta mutants exhibit mitotic and cytokinesis defects under conditions of osmotic stress that bear resemblance to defects observed in proteasome-defective mutants of S. pombe. They are also able to mate on rich media, a phenotype characteristic of mutants defective in function for the cAMP pathway. These phenotypes are distinct from those caused by loss of function of previously characterized stress response pathways in S. pombe, suggesting that Plb1 regulates a novel pathway. Consistent with the phenotypes caused by loss of Plb1 function, a screen for multi-copy suppressors of the osmosensitive growth defect of plb1 mutant cells resulted in the isolation of genes encoding activators of adenylate cyclase, a 26S proteasome subunit (pra7), and several genes encoding novel proteins, several of which are conserved in mammals. We have determined that the cAMP pathway, like PIb1, is essential for survival of S. pombe cells in hyperosmotic media and that loss of function of the cAMP pathway is rescued by several multi-copy suppressors of plb1delta, including pra7. Our findings lead us to hypothesize that PIb1 functions, in part, to regulate cell cycle progression under conditions of osmotic stress through a novel cAMP and 26S proteasomemediated pathway. We will use the power of yeast genetics, in combination with molecular and biochemical approaches, to further characterize the Plb1-dependent stress response pathway(s) in S. pombe. Our Specific Aims are to: (1) define the enzymatic activities and subcellular localization of Plb1 and determine whether they are altered in response to osmotic stress, (2) establish functional relationships between Plb1 and previously characterized osmotic stress response pathways in fission yeast, (3) investigate roles for the cAMP pathway and 26S proteasome in mediating Plb1-dependent stress response functions, and (4) determine whether other multicopy suppressors of plb1? encode components of the PIb1-dependent stress response pathway. We anticipate that our proposed studies will provide insights into novel mechanisms of stress-induced signal transduction and cell cycle regulation that are likely to be conserved in higher organisms. The proposed project is relevant to several human diseases, including cardiovascular, inflammatory, neurodesenerative, and neoplastic diseases.

描述（由申请人提供）： 磷脂酶B（PLB）酶在生物学功能方面包括最了解的磷脂酶类别。尽管已经在遗传性酵母中鉴定出了几种PLB同工酶，但它们的生理功能在很大程度上尚不清楚。 We have elucidated a role for a newly identified member of the fungal PLB family, Plbl, as an essential mediator of osmotic stress response in the fission yeast, Schizosaccharomyces pombe, plb 1delta mutants exhibit mitotic and cytokinesis defects under conditions of osmotic stress that bear resemblance to defects observed in proteasome-defective mutants of S. pombe.他们还能够在Rich Media上交配，这是突变体在营地路径功能中有缺陷的表型特征。这些表型不同于由先前表征的应力反应途径在S. pombe中的功能丧失引起的，这表明PLB1调节了新的途径。与PLB1功能丧失引起的表型一致，PLB1突变细胞的渗透敏感生长缺陷的多拷贝抑制子的筛选导致隔离编码腺苷酸环酶的基因，A 26S蛋白酶体亚基（PRA7）（PRA7）和几种编码新颖的小型原始人物，几个基因，几个基因，几个基因，几个基因，几个基因均受MAMM的影响。我们已经确定，像PIB1一样，cAMP通路对于高渗介质中的Pombe细胞的存活至关重要，并且包括PRA7在内的几个多拷贝抑制器（包括PRA7）挽救了营地途径的功能丧失。我们的发现使我们假设PIB1在渗透应激条件下通过新型cAMP和26S蛋白酶体介导的途径在渗透应激条件下的一部分起作用。我们将使用酵母遗传学的力量与分子和生化方法结合使用，以进一步表征S. pombe中PLB1依赖性应激响应途径。我们的具体目的是：（1）定义PLB1的酶活性和亚细胞定位，并确定它们是否会因响应渗透压而改变它们，（（2））在PLB1和先前表征的裂解酵母中表征的渗透压响应途径之间建立功能关系，（3）在cAMP途径和26S progient protional protional protions protions（3）中是否依赖PLB1的作用（3） PLB1？编码依赖PIB1的应力响应途径的组件。我们预计，我们提出的研究将提供有关应激诱导的信号转导和细胞周期调节的新机制的见解，这些机制可能在较高的生物体中保守。拟议的项目与几种人类疾病有关，包括心血管，炎症，神经霉素和肿瘤疾病。