亮氨酸拉链结构域在 p57 与 actin结合中的重要作用

Actin 结合蛋白 p57 与 actin 之间存在相当复杂的作用机制 . 为深入了解这一机制，利用体外 F-actin 结合共沉淀、细胞内免疫荧光共定位以及免疫印迹和吸光度扫描分析等实验技术，系统地研究了亮氨酸拉链结构域在 p57 与 actin 结合中的作用 . 结果显示，亮氨酸拉链序列区域本身没有 actin 结合活性，但该区域缺失突变以及破坏亮氨酸拉链结构域的点突变都可以显著降低 p57 同 actin 的结合能力 . 同时，体内和体外的半定量分析结果表明，这两种突变导致 p57 同 actin 的结合能力的降低程度十分相近 . 这些结果充分说明亮氨酸拉链结构域在 p57 与 actin 的结合中起到了重要作用 .

Leucine Zipper Domain is Important for Actin Binding of p57

The role of the leucine zipper domain in actin binding of p57 was investigated by the methods of the F-actin co-sedimentation studies in vitro, the immunofluorescence co-localization analyses in cells, the Western blot and density scan assays. The results showed that the leucine zipper-containing domain alone has no actin-binding activity, while the C-terminal deletion mutation removing this domain or the point mutation destroying leucine zipper domain leads to great reduction of actin-binding activity of p57. Furthermore, the degrees of degradation in actin-binding activity caused by the two mutations were assessed in quasi-quantitative analysis in vitro and in cells and both mutations exhibited the extremely similar depressing effects. These data strongly suggest that the leucine zipper domain is important for actin binding of p57.