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A novel role for polysaccharide monooxygenases in signaling, chemotropic interactions and cell fusion

多糖单加氧酶在信号传导、趋化相互作用和细胞融合中的新作用

基本信息

批准号：
1818283
负责人：
N Louise Glass
金额：
$ 90万
依托单位：
University of California-Berkeley
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-01 至 2023-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1818283&HistoricalAwards=false
关键词：
novel role polysaccharide monooxygenases signaling

项目摘要

It has been estimated that up to one quarter of the world's biomass is of fungal origin, comprising approximately six million species. To interact with one another and respond to environmental cues, these species communicate and respond via chemical languages. In filamentous ascomycete fungi, the formation of an interconnected, multinucleate hyphal network is constructed via communication and fusion of germinated asexual spores (germlings) and hyphae. In nature, filamentous fungi play important roles in decomposition of plant and animal matter, nutrient cycling and nutrient transport in the hyphal network, including an association with plants, both as symbionts and as pathogens. This project defines a new biological function during hyphal network formation for a class of oxidative enzymes, termed polysaccharide monooxygenases (PMOs), that play a role during signaling, chemotropic interactions and cell wall remodeling during somatic cell fusion in filamentous fungi. Previously, this class of enzymes has only been associated with extracellular degradative capacities, providing a paradigm shift in the cellular function of this class of proteins. The discovery of a role for copper-dependent PMOs in cell signaling, along with the characterization of new substrates for these enzymes, will greatly impact this field of research; genes encoding PMOs have been found in human and plant pathogens and may also be involved in symbiotic relationships. This project brings expertise on cell signaling, cell biology and genetics with deep expertise in biochemistry and structural biology on PMOs, and provides an excellent training opportunity for undergraduate, graduate students and postdoctoral associates. Workshops will be developed on the use of the filamentous fungus Neurospora crassa to identify and characterize molecular players involved in cell-cell communication and fusion in collaboration with educational science organizations and will form the basis of an intensive three-week undergraduate course at the University of California - Berkeley. Live cell imaging movies from this project and others will enrich educational aspects on the role of fungi in the environment in exhibitions provided by the Mycological Society of San Francisco and the Bay Area Mycological Society. Chemotropic interactions between fungal germlings (or hyphae in a colony), initiates cell communication, followed by a switch from cell growth to cell wall breakdown and membrane merger at the contact point between adhered cells. A role for a predicted PMO, HAM-7, is required for chemotropic interactions and functions through the cell wall integrity (CWI) MAP kinase signaling pathway in filamentous fungi. Strains lacking ham-7 fail to undergo cell fusion and thus lack an interconnected hyphal network. The ham-7 gene and its relatives form a unique clade among PMOs in fungi. The substrate for the HAM-7 PMO is currently unknown and defining the activity of HAM-7, its substrate and role in chemotropic interactions and cell fusion using biochemical methods, structural biology, cell biology and genetics is a major objective of this project. A second PMO, CWR-1, which is predicted to use chitin as a substrate based on homology, functions as a negative regulator of the switch from cell growth to cell wall disassembly during cell fusion. A predicted membrane protein, CWR-3 is required for CWR-1 to function in cell wall disassembly, suggesting it may function as a receptor for the product of the CWR-1 enzymatic activity. This project will link the function of polysaccharide monooxygenases oxidative capacity with the enigmatic properties of chemical languages involved in germling/hyphal communication that dictates the behavior of cells seeking to undergo vegetative fusion with their own kind. The work described in this project will be transformative in defining new biological roles for this class of enzymes/proteins that may be broadly applicable to both eukaryotic and prokaryotic species that encode PMOs in their genomes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

据估计，世界上多达四分之一的生物量是真菌来源的，包括大约600万个物种。为了相互作用并对环境线索做出反应，这些物种通过化学语言进行交流和反应。在丝状子囊菌中，通过萌发的无性孢子（胚）和菌丝的通讯和融合，形成了一个相互连接的多核菌丝网络。在自然界中，丝状真菌在植物和动物物质的分解、营养循环和菌丝网络中的营养运输中发挥重要作用，包括作为共生体和病原体与植物的关联。该项目定义了一类称为多糖单加氧酶（PMO）的氧化酶在菌丝网络形成过程中的新生物学功能，这些氧化酶在丝状真菌体细胞融合过程中的信号传导，趋化性相互作用和细胞壁重塑中发挥作用。以前，这类酶仅与细胞外降解能力相关，这类蛋白质的细胞功能发生了范式转变。铜依赖性PMO在细胞信号传导中的作用的发现，沿着这些酶的新底物的表征，将极大地影响这一研究领域;编码PMO的基因已在人类和植物病原体中发现，并且也可能参与共生关系。该项目带来了细胞信号传导，细胞生物学和遗传学方面的专业知识，并在生物化学和结构生物学方面具有深厚的专业知识，为本科生，研究生和博士后提供了极好的培训机会。将与教育科学组织合作，举办关于利用丝状真菌粗糙脉孢菌鉴定和描述参与细胞间通讯和融合的分子的讲习班，并将作为加州-伯克利大学为期三周的密集本科课程的基础。活细胞成像电影从这个项目和其他人将丰富教育方面的作用，真菌在环境中的展览提供的真菌学会旧金山弗朗西斯科和湾区真菌学会。真菌胚（或菌落中的菌丝）之间的趋化性相互作用启动细胞通讯，随后从细胞生长转变为细胞壁破裂和在粘附细胞之间的接触点处的膜合并。预测的PMO，HAM-7的作用，需要通过丝状真菌中的细胞壁完整性（CWI）MAP激酶信号通路的趋化性相互作用和功能。缺乏ham-7的菌株不能进行细胞融合，因此缺乏相互连接的菌丝网络。ham-7基因及其相关基因在真菌的PMO中形成了一个独特的分支。HAM-7 PMO的底物目前尚不清楚，使用生物化学方法、结构生物学、细胞生物学和遗传学定义HAM-7的活性、其底物和在趋化性相互作用和细胞融合中的作用是该项目的主要目标。第二个PMO，CWR-1，这是预测使用几丁质作为底物的基础上同源性，作为一个负调节器的开关从细胞生长到细胞壁解体在细胞融合。预测的膜蛋白CWR-3是CWR-1在细胞壁解体中发挥作用所必需的，这表明它可能作为CWR-1酶活性产物的受体发挥作用。该项目将把多糖单加氧酶的氧化能力的功能与涉及胚/菌丝通讯的化学语言的神秘特性联系起来，这些化学语言决定了细胞寻求与自己的种类进行营养融合的行为。在这个项目中描述的工作将在定义这类酶/蛋白质的新的生物学作用方面具有变革性，这些酶/蛋白质可能广泛适用于在其基因组中编码PMO的真核生物和原核生物物种。这个奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。