Structure of plant actomyosin and its function in cells.

点击翻译按钮获取中文摘要

1) Purification and characterization of myosin : We succeeded in purifying myosin from pollen tubes of lily. Molecular weight of the myosin was about 150 kDa. This is the first success in purifying myosin showing sliding activity along actin filaments from plants. ATPase and sliding activity along actin filaments was inhibited by calcium. It is generally accepted that cytoplasmic streaming is inhibited by calcium in plant cells. Inhibition of myosin activity demonstrated in the present study is the molecular basis of calcium regulation of cytoplasmic streaming. We also succeeded in preparing antibody against this myosin. Using this myosin antibody, we analyzed distribution of this myosin in various plant cells.2) Reverse fountain streaming : In root hair cells of Hydrocharis, we can observed reverse fountain streaming. Using inhibitors of actin, we unequivocally demonstrated that actin is involved in maintenance of structure of transvacuolar strands and occurrence of cytoplasmic streaming. It was also demonstrated that microtubules are involved in maintenance of organization of actin filaments in the cell.3) Purification of actin binding protein : It is generally accepted that actin binding proteins are involved in organization of actin filaments. However, studies on actin binding protein is scanty in plant cells. We succeeded in purifying actin bundling protein from pollen tubes of lily. We analyzed various characteristics of the actin-bundling protein. This is the first success in purifying actin-bundling protein from plant cells.