Osmotic Stress Modulates the Balance between Exocytosis and Clathrin-Mediated Endocytosis in Arabidopsis thaliana  

作　　者：Marta Zwiewka Tomasz Nodzynski Stephanie Robert Steffen Vanneste Jiri Friml 

机构地区：[1]Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, CZ-625 00 Brno,Czech Republic [2]Department of Plant Systems Biology, VlB and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Gent, Belgium [3]Institute of Science and Technology (IST) Austria, Am Campus 1, 3400 Klosterneuburg, Austria [4]Present address: Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences/Ume~. Plant Science Center, 901 83 Umea,Sweden

出　　处：《Molecular Plant》2015年第8期1175-1187,共13页分子植物（英文版）

摘　　要：The sessile life style of plants creates the need to deal with an often adverse environment, in which water availability can change on a daily basis, challenging the cellular physiology and integrity. Changes in os- motic conditions disrupt the equilibrium of the plasma membrane： hypoosmotic conditions increase and hyperosmotic environment decrease the cell volume. Here, we show that short-term extracellular osmotic treatments are closely followed by a shift in the balance between endocytosis and exocytosis in root mer- istem cells. Acute hyperosmotic treatments （ionic and nonionic） enhance clathrin-mediated endocytosis simultaneously attenuating exocytosis, whereas hypoosmotic treatments have the opposite effects. In addition to clathrin recruitment to the plasma membrane, components of early endocytic trafficking are essential during hyperosmotic stress responses. Consequently, growth of seedlings defective in elements of clathrin or early endocytic machinery is more sensitive to hyperosmotic treatments. We also found that the endocytotic response to a change of osmotic status in the environment is dominant over the presum- ably evolutionary more recent regulatory effect of plant hormones, such as auxin. These results imply that osmotic perturbation influences the balance between endocytosis and exocytosis acting through clathrin- mediated endocytosis. We propose that tension on the plasma membrane determines the addition or removal of membranes at the cell surface, thus preserving cell integrity.The sessile life style of plants creates the need to deal with an often adverse environment, in which water availability can change on a daily basis, challenging the cellular physiology and integrity. Changes in os- motic conditions disrupt the equilibrium of the plasma membrane： hypoosmotic conditions increase and hyperosmotic environment decrease the cell volume. Here, we show that short-term extracellular osmotic treatments are closely followed by a shift in the balance between endocytosis and exocytosis in root mer- istem cells. Acute hyperosmotic treatments （ionic and nonionic） enhance clathrin-mediated endocytosis simultaneously attenuating exocytosis, whereas hypoosmotic treatments have the opposite effects. In addition to clathrin recruitment to the plasma membrane, components of early endocytic trafficking are essential during hyperosmotic stress responses. Consequently, growth of seedlings defective in elements of clathrin or early endocytic machinery is more sensitive to hyperosmotic treatments. We also found that the endocytotic response to a change of osmotic status in the environment is dominant over the presum- ably evolutionary more recent regulatory effect of plant hormones, such as auxin. These results imply that osmotic perturbation influences the balance between endocytosis and exocytosis acting through clathrin- mediated endocytosis. We propose that tension on the plasma membrane determines the addition or removal of membranes at the cell surface, thus preserving cell integrity.

关 键 词：osmotic stress protein trafficking clathrin-mediated endocytosis AUXIN 

分 类 号：Q959.4[生物学—动物学] TS108.3[轻工技术与工程—纺织工程]