Kock Christian, Arlt Henning, Ungermann Christian, Heinisch Jürgen J
Universität Osnabrück, Fachbereich Biologie/Chemie, AG Genetik, 49076, Osnabrück, Germany.
Universität Osnabrück, Fachbereich Biologie/Chemie, AG Biochemie, 49076, Osnabrück, Germany.
Cell Microbiol. 2016 Sep;18(9):1251-67. doi: 10.1111/cmi.12635. Epub 2016 Jul 22.
The cell wall integrity (CWI) pathway of the yeast Saccharomyces cerevisiae relies on the detection of cell surface stress by five sensors (Wsc1, Wsc2, Wsc3, Mid2, Mtl1). Each sensor contains a single transmembrane domain and a highly mannosylated extracellular region, and probably detects mechanical stress in the cell wall or the plasma membrane. We here studied the distribution of the five sensors at the cell surface by using fluorescently tagged variants in conjunction with marker proteins for established membrane compartments. We find that each of the sensors occupies a specific microdomain at the plasma membrane. The novel punctate 'membrane compartment occupied by Wsc1' (MCW) shows moderate overlap with other Wsc-type sensors, but not with those of the Mid-type sensors or other established plasma membrane domains. We further observed that sensor density and formation of the MCW compartment depends on the cysteine-rich head group near the N-terminus of Wsc1. Yet, signalling capacity depends more on the sensor density in the plasma membrane than on clustering within its microcompartment. We propose that the MCW microcompartment provides a quality control mechanism for retaining functional sensors at the plasma membrane to prevent them from endocytosis.
酿酒酵母的细胞壁完整性（CWI）途径依赖于五种传感器（Wsc1、Wsc2、Wsc3、Mid2、Mtl1）对细胞表面应激的检测。每种传感器都包含一个单一的跨膜结构域和一个高度糖基化的细胞外区域，可能检测细胞壁或质膜中的机械应激。我们在此通过使用荧光标记变体结合已建立膜区室的标记蛋白，研究了这五种传感器在细胞表面的分布。我们发现每种传感器在质膜上占据一个特定的微区。新的点状“被Wsc1占据的膜区室”（MCW）与其他Wsc型传感器有适度重叠，但与Mid型传感器或其他已建立的质膜结构域没有重叠。我们进一步观察到，传感器密度和MCW区室的形成取决于Wsc1 N端附近富含半胱氨酸的头部基团。然而，信号传导能力更多地取决于质膜中的传感器密度，而不是其微区室内的聚集。我们提出，MCW微区室提供了一种质量控制机制，用于将功能性传感器保留在质膜上，以防止它们被内吞。
