DYNAMICS OF CELLULAR FUNCTION OF PLANT VACUOLES.

点击翻译按钮获取中文摘要

Vacuole is one on the most conspicuous compartments within a plant cell. We have investigated dynamic aspect of plant vacuoles in function and morphology. The vacuole performs numerous functions vital to cellular homeostasis, including the accumulation of metabolites, storage proteins and inorganic ions. The vacuolar function is supported by the primary and secondary active transport systems. We focused our attention on the vacuolar proton pumps which acidify vacuoles and create a membrane potential. Also, Na^+/H^+antiporter has been characterized as the secondary active transporter. The most important aspect of vacuoles is their role in protein storage. The protein storage vacuoles are derived from central vacuoles in the maturating seeds and transformed to a central vacuole in the germinating seeds. We analyzed the mechanisms for the protein accumulation into these protein-storage vacuoles and for the transformation between the protein-storage vacuole and the central vacuole. And the mechanisms of vacuolar morphogenesis and the molecular basis of autophagic function have been investigated for yeast and plant cells.Our investigations revealed the physiological significance of vacuolar proton pumps in the ion accumulation, intracellular sorting of storage protein to vacuole and cell expansion. Nishimura's group found the dense vesicles that act as transport vesicles from ER to vacuoles for storage proteins in seeds. In yeast systems, the essential genes and protein factor for vacuole morphogenesis have been identified. Ohsumi's group found the autophagy in yeast cells and analyzed the process at levels of cell biology and molecular genetics. During this study, some fruitful, cooperative works among the members have been done.