Isolation of concanavalin a caps during various stages of formation and their association with actin and myosin
Isolation of concanavalin a caps during various stages of formation and their association with actin and myosin
复制标题
刀豆球蛋白a帽在形成的各个阶段的分离及其与肌动蛋白和肌球蛋白的关联
DOI：
--
复制
发表时间：
1979
影响因子：
7.8
通讯作者：
J. Condeelis
中科院分区：
文献类型：
--
作者：
J. Condeelis
含有cona受体复合物的盘状变形虫dictyostelium disideum amoeba质膜区域更能抵抗Triton X-100的破坏。这种抗性使得Con a相关膜片段的分离成为可能，其数量和均匀性足以对细胞膜上的受体-细胞骨架相互作用进行直接的生化和超微结构研究。Con A与细胞表面特异性结合后，细胞内大量的肌动蛋白和肌球蛋白与质膜碎片发生融合。肌凝蛋白比肌动蛋白更松散地结合在分离的膜上，通过ATP和低离子强度处理膜可以有效地去除肌凝蛋白。如果细胞在凝集素结合后没有立即被分解，那么所有与细胞表面结合的Con A都会在一个需要代谢能量的过程中被扫进一个帽状结构中。当细胞在帽形成的不同阶段被裂解时，与分离膜结合的肌动蛋白和肌球蛋白的数量保持不变。在帽形成的所有阶段，附着在分离膜的原生质表面的粗细细丝是凝集素受体复合物的基础。一旦帽状结构完成，与质膜紧密结合的肌动蛋白和肌凝蛋白就会随着Con - a受体复合物一起被浓缩到帽状结构中。这些结果表明，atp依赖的膜相关肌动蛋白和肌球蛋白丝的滑动是Con -a受体复合物在细胞表面堆积成帽状的原因。
Regions of plasma membrane of dictyostelium discoideum amoebae that contain concanavalin A (Con A)-receptor complexes are more resistant to disruption by Triton X-100. This resistance makes possible the isolation of Con A-associated membrane fragments in sufficient quantity and homogeneity to permit the direct biochemical and ultrastructural study of receptor-cytoskeletal interactions across the cell membrane. After specific binding of Con A to the cell surface, a large amount of the cell’s actin and myosin copurifies with the plasma membrane fragments. Myosin is more loosely bound to the isolated membranes that actin and is efficiently removed by treating membranes with ATP and low ionic strength. If cells are not lysed immediately after lectin binding, all of the Con A that is bound to the cell surface is swept into a cap in a process requiring metabolic energy. When cells are lysed at different stages of cap formation, the amount of actin and myosin that copurifies with the isolated membranes remains the same. Thick and thin filaments that are attached to the protoplasmic surface of the isolated membranes underlie lectin-receptor complexes during all stages of cap formation. Once the cap is complete, the amount of actin and myosin that tightly bound to the plasma membrane is concentrated into the cap along with the Con A-receptor complexes. These results suggest that the ATP-dependent sliding of membrane-associated actin and myosin filaments is responsible for the accumulation of Con A-receptor complexes into a cap on the cell surface.