Modes of Exocytotic and Endocytotic Events in Tobacco BY-2 Protoplasts  

作　　者：Vera Bandmann Marko Kreft Ulrike Homann 

机构地区：[1]Institut fur Botanik, Technische Universitat Darmstadt, 64287 Darmstadt, Germany [2]Laboratory of Neuroendocrinology and Molecular Cell Physiology, University of Ljubljana and Celica Biomedical Center, Technology Park 24, 1000 Ljubljana, Slovenia

出　　处：《Molecular Plant》2011年第2期241-251,共11页分子植物（英文版）

摘　　要：To analyze the kinetics and size of single exo- and endocytotic events in BY-2 protoplasts, we employed cellattached membrane capacitance measurements. These measurements revealed different modes of fusion and fission of single vesicles. In about half of the observed exocytotic events, fusion occurred transiently, which facilitates rapid recycling of vesicles. In addition, transient sequential or multi-vesicular exocytosis observed in some recordings can contribute to an increase in efficiency of secretory product release. Microscopic analysis of the timescale of cellulose and pectin deposition in protoplasts demonstrates that rebuilding of the cell wall starts soon after isolation of protoplasts and that transient fusion events can fully account for secretion of the required soluble material. The capacitance measurements also allowed us to investigate formation of the fusion pore. We speculate that regulation of secretion may involve control of the length and/or size of fusion pore opening. Together, the different kinetic modes of exo- and endocytosis revealed by capacitance measurements underline the complexity of this process in plants and provide a basis for future research into the underlying mechanisms. The fact that similar fusion/fission kinetics are present in plant and animal cells suggests that many of these mechanisms are highly conserved among eukaryotes.To analyze the kinetics and size of single exo- and endocytotic events in BY-2 protoplasts, we employed cellattached membrane capacitance measurements. These measurements revealed different modes of fusion and fission of single vesicles. In about half of the observed exocytotic events, fusion occurred transiently, which facilitates rapid recycling of vesicles. In addition, transient sequential or multi-vesicular exocytosis observed in some recordings can contribute to an increase in efficiency of secretory product release. Microscopic analysis of the timescale of cellulose and pectin deposition in protoplasts demonstrates that rebuilding of the cell wall starts soon after isolation of protoplasts and that transient fusion events can fully account for secretion of the required soluble material. The capacitance measurements also allowed us to investigate formation of the fusion pore. We speculate that regulation of secretion may involve control of the length and/or size of fusion pore opening. Together, the different kinetic modes of exo- and endocytosis revealed by capacitance measurements underline the complexity of this process in plants and provide a basis for future research into the underlying mechanisms. The fact that similar fusion/fission kinetics are present in plant and animal cells suggests that many of these mechanisms are highly conserved among eukaryotes.

关 键 词：ELECTROPHYSIOLOGY cell walls protein traffic and secretion BY-2 ENDOCYTOSIS exocytosis. 

分 类 号：Q51[生物学—生物化学] TS261.11[轻工技术与工程—发酵工程]