Analysis of the spatial distribution of the key components of the HOG signaling pathway, TcsC and Ypd1, and its impact on their function in the pathogenic mold Aspergillus fumigatus.

高渗透压甘油（HOG）途径是特别有趣的，首先，作为一个范例的真菌信号级联，其次，因为它的传感激酶TcsC代表了一个有吸引力的新的抗真菌治疗的目标结构。我们的目的是研究HOG途径的初始部分的空间组织，所谓的双组分磷酸化，并确定其对相应蛋白质的功能的影响，例如，它们组织对高渗应激的适应性反应的能力。我们的初步研究结果显示了新的和意想不到的定位模式的HOG两个关键组成部分的两个组件磷酸化在A。fumigatus、TcsC和Ypd 1.这使我们产生了一个新的假设，并且所提出的项目旨在验证我们的概念：传感器激酶TcsC在环境条件下驻留在细胞核中并在激活后易位到细胞质的事实提供了一个强烈的暗示，即曲霉菌在细胞核中感知高渗应力。我们假设这发生在核膜上，并涉及一个尚未表征的A。烟曲霉SUN结构域蛋白，该蛋白又被认为是连接核膜与细胞骨架的结构的一部分。如果是正确的，这将建立一个全新的模型，丝状真菌如何感知高渗胁迫。在这个项目中，我们还将确定潜在的TcsC多聚化对其功能和在细胞核和细胞质之间穿梭的影响。最后，我们将确定所观察到的激活Ypd 1从细胞质到细胞核的易位的功能相关性，并定义Ypd 1的相关结构域/基序。

The High Osmolarity Glycerol (HOG) pathway is particular interesting, firstly, as a paradigm for a fungal signaling cascade and secondly, because its sensing kinase TcsC represents an attractive target structure for new antifungal therapies. Our aim is to study the spatial organization of the initial part of the HOG pathway, the so-called two-component phosphorelay, and to define its impact on the function of the respective proteins, e.g. their ability to organize an adaptive response to hyperosmotic stress. Our preliminary results show novel and unexpected localization patterns for two key components of HOG two-component phosphorelay in A. fumigatus, TcsC and Ypd1. This led us to a new hypothesis, and the proposed project aims to verify our concept:The fact that the sensor kinase TcsC resides in the nucleus at ambient conditions and translocates to the cytoplasm upon activation provides a strong hint that Aspergillus senses hyperosmotic stress in the nucleus. We hypothesize that this takes place at the nuclear membrane and involves a yet uncharacterized A. fumigatus SUN-domain protein that in turn is assumed to be part of a structure that connects the nuclear membrane to the cytoskeleton. If correct, this would establish a completely new model of how filamentous fungi sense hyperosmotic stress. In this project, we will also define the impact of a potential TcsC multimerization on its function and shuttling between the nucleus and the cytoplasm. Finally, we will determine the functional relevance of the observed translocation of activated Ypd1 from the cytoplasm to the nucleus and define the relevant domains/motifs of Ypd1.