Regulation of Yeast Filamentous Morphogenesis By Inositol Polyphosphates

该项目将确定真菌生长的关键步骤，以开发与农业和其他经济部门相关的抗真菌药物。真菌细胞在一定程度上通过控制细胞内充当信使的分子的丰度来调节自己的生长，以响应营养的可获得性。一类这样的信使，肌醇多磷酸(INSP)，有助于控制真菌生物膜垫的细胞形状和由此产生的物理性质，真菌生物膜垫是在塑料和其他固体表面形成的耐真菌细胞片。对这些Insp信使或它们附着的细胞组件的调节知之甚少。这项研究将提供关于Insp信使及其对真菌生物学和生长的影响的缺失的分子和生物物理细节。这一水平的理解对于开发控制真菌过度生长的新方法是至关重要的。从教育的角度来看，来自代表性不足背景的本科生将有机会接受关于INSP分析的分子和细胞生物学的暑期培训。这些学生还将参加部门活动和多样性研讨会，为他们提供更好地在研究生教育环境中取得成功的背景和基础资源。细胞使用代谢物水平来发出营养应激条件的信号，以调节细胞形状、细胞周期进程、基因表达和极化生长，但这种信号的分子基础尚不完全清楚。酿酒酵母和白色念珠菌是细胞信号的高度信息量的真菌模型。在营养限制的条件下，酵母细胞通过最近发现的信号网络形成延伸和连接的丝状物，如假菌丝、菌丝和生物膜，该信号网络涉及一种重要和保守的代谢物--多聚肌醇(INSP)的调控。INSP是六碳肌醇环的磷酸化变体，调节不同的细胞过程。在营养限制条件下，酵母细胞生长和丝状化所需的途径对于野生型INSP水平是必需的，而编码INSP生物合成酶的基因是野生型丝状化所必需的。特别是，在肌醇环上具有双磷酸碳残基的焦磷酸化INSP物种的各自水平与酿酒酵母中的丝状化程度密切相关。这项研究将剖析细丝形成和生物膜形成的调节与INSP信号转导之间的分子机制。保守的AMPK家族激酶Snf1p在调节Insp激酶Kcs1p和Vip1p活性中的分子功能将被确定。本研究确定了Insps在控制质膜蛋白质组成和结构中的作用。INSP信号对白念珠菌生物膜丝状形态和流变性的影响将被量化。总而言之，该项目研究了调节InSP丰度的保守信号通路和这个调节网络的新的下游效应器。此外，这项研究量化了INSP信号对白色念珠菌生物膜生物物理的影响，在理解这种具有经济意义的真菌多细胞结构的分子基础方面取得了重要进展。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will define critical steps in fungal growth for the development of antifungal agents, relevant to the agricultural industry and other economic sectors. Fungal cells regulate their growth in response to nutrient availability in part by controlling the abundance of molecules that can act as messengers within cells. One such class of messengers, inositol polyphosphates (InsPs), contribute to the control of cell shape and the resulting physical properties of fungal biofilm mats, resistant sheets of fungal cells that form on plastics and other solid surfaces. Little is known about the regulation of these InsP messengers or the cell components to which they attach. This research will provide missing molecular and biophysical detail regarding InsP messengers and their effect on fungal biology and growth. This level of understanding is fundamental for the development of new methods to control fungal overgrowth. From an educational perspective, undergraduate students from underrepresented backgrounds will have the opportunity to receive summer training in molecular and cellular biology for the analysis of InsPs. These students will also participate in departmental events and diversity workshops to provide them with the background and foundational resources to better succeed in graduate educational settings.Cells use metabolite levels to signal conditions of nutritional stress for the regulation of cell shape, cell cycle progression, gene expression, and polarized growth, but the molecular basis of this signaling is incompletely understood. The yeasts S. cerevisiae and C. albicans are highly informative fungal models of cell signaling. Under conditions of nutrient limitation, yeast cells form extended and connected filaments as pseudohyphae, hyphae, and biofilms, through a signaling network recently found to involve the regulatory control of an important and conserved metabolite, inositol polyphosphate (InsP). InsPs are phosphorylated variants of the six-carbon inositol ring that regulate diverse cell processes. Pathways required for yeast cell growth and filamentation are required for wild-type InsP levels under conditions of nutrient limitation, and the genes encoding InsP biosynthetic enzymes are required for wild-type filamentation. In particular, the respective levels of pyrophosphorylated InsP species with doubly phosphorylated carbon residues in the inositol ring correlates strongly with the degree of filamentation in S. cerevisiae. This research will dissect the molecular mechanisms linking the regulation of filamentation and biofilm formation with InsP signaling. The molecular function of the conserved AMPK family kinase Snf1p in modulating activity of the InsP kinases Kcs1p and Vip1p will be determined. This research identifies the role of InsPs in controlling the protein composition and structure of the plasma membrane. The effect of InsP signaling on the filamentous morphology and rheological properties of biofilms in C. albicans will be quantified. Collectively, the project investigates conserved signaling pathways regulating InsP abundance and new downstream effectors of this regulatory network. Further, the research quantifies the effects of InsP signaling on the biophysics of C. albicans biofilms, presenting an important advancement in understanding the molecular basis of this economically significant fungal multicellular structure.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.