Plant PIEZO homologs modulate vacuole morphology during tip growth

背景回顾：In animals, PIEZOs are plasma membrane–localized cation channels involved in diverse mechanosensory processes. 

主要研究：We investigated PIEZO function in tip-growing cells in the moss Physcomitrium patens and the flowering plant Arabidopsis thaliana.

结果1-苔藓PIEZO1/2功能冗余：PpPIEZO1 and PpPIEZO2 redundantly contribute to the normal growth, size, and cytoplasmic calcium oscillations of caulonemal cells. 

结果2-PpPIEZO1/2亚细胞定位：Both PpPIEZO1 and PpPIEZO2 localized to vacuolar membranes. 

结果3-PpPIEZO1/2作用机制：Loss-of-function, gain-of-function, and overexpression mutants revealed that moss PIEZO homologs promote increased complexity of vacuolar membranes through tubulation, internalization, and/or fission.

结果4-拟南芥PIEZO1亚细胞定位+功能： ArabidopsisPIEZO1 also localized to the tonoplast and is required for vacuole tubulation in the tips of pollen tubes. 

结论：We propose that in plant cells the tonoplast has more freedom of movement than the plasma membrane, making it a more effective location for mechanosensory proteins.

 摘 要 

在动物中，PIEZOs是一类定位于质膜的阳离子通道，参与各种机械感知过程。本文中，作者研究了小立碗藓和拟南芥的PIEZO在尖端生长中的功能。PpPIEZO1和PpPIEZO2在小立碗藓轴丝体细胞的正常生长、大小和钙离子震荡方面存在功能冗余。PpPIEZO1和PpPIEZO2均定位于液泡膜。功能缺失突变体、功能获得突变体以及过表达株系的研究显示，苔藓PIEZO同源蛋白能够通过管状化、内陷或者膜分裂促进液泡膜的复杂度增加。拟南芥PIEZO1蛋白同样定位于液泡膜，并且作用于花粉管顶端细胞的液泡管状化。据此，作者提出植物液泡膜上的细胞具有比质膜细胞更为自由的移动能力，使其成为植物中作用于机械力感知蛋白的有利位置。