Yeast cell wall integrity sensors form specific plasma membrane microdomains important for signalling
Yeast cell wall integrity sensors form specific plasma membrane microdomains important for signalling
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DOI：
10.1111/cmi.12635
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发表时间：
2016-09-01
影响因子：
3.4
通讯作者：
Heinisch, Juergen J.
中科院分区：
文献类型：
--
作者：
Kock, Christian;Arlt, Henning;Heinisch, Juergen J.
酿酒酵母的细胞壁完整性（CWI）途径依赖于通过五种传感器（Wsc 1、Wsc 2、Wsc 3、Mid 2、Mtl 1）检测细胞表面应力。每个传感器包含一个单一的跨膜结构域和一个高度甘露糖基化的细胞外区域，并可能检测细胞壁或质膜中的机械应力。在这里，我们研究了分布的五个传感器在细胞表面，通过使用荧光标记的变体与标记蛋白结合建立膜室。我们发现，每个传感器占据一个特定的微区在质膜。由Wsc 1 ′（MCW）占据的新的点状膜室显示出与其它Wsc型传感器的适度重叠，但不与中间型传感器或其它已建立的质膜结构域的那些重叠。我们进一步观察到，传感器密度和MCW隔室的形成取决于Wsc 1的N-末端附近的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类。我们建议，MCW微区室提供了一个质量控制机制，保留在质膜上的功能传感器，以防止它们的内吞作用。
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.