Structure of plant actomyosin and its function in cells.

1)肌球蛋白的纯化及性质：我们成功地从百合花粉管中纯化了肌球蛋白。肌球蛋白的分子量约为150 kDa。这是从植物中纯化肌球蛋白的首次成功，该肌球蛋白显示出沿沿着滑动的活性。ATP酶和沿着肌动蛋白丝的滑动活性被钙抑制。一般认为，植物细胞中钙离子对细胞质流动有抑制作用。本研究证实肌球蛋白活性的抑制是钙调节细胞质流动的分子基础。我们还成功地制备了抗该肌球蛋白的抗体。利用该抗体分析了该肌球蛋白在不同植物细胞中的分布。2）反向喷泉流：在水鳖属植物的根毛细胞中，可以观察到反向喷泉流。使用肌动蛋白的抑制剂，我们明确地表明，肌动蛋白是参与维持结构的transvacuolar链和发生的细胞质流。微管参与维持细胞内肌动蛋白丝的组织。3）肌动蛋白结合蛋白的纯化：人们普遍认为肌动蛋白结合蛋白参与肌动蛋白丝的组织。然而，在植物细胞中对肌动蛋白结合蛋白的研究却很少。我们成功地从百合花粉管中纯化了肌动蛋白捆绑蛋白。我们分析了肌动蛋白捆绑蛋白的各种特性。这是首次从植物细胞中成功纯化肌动蛋白捆绑蛋白。

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.