Cytochalasins inhibit nuclei-induced actin polymerization by blocking filament elongation.
Cytochalasins inhibit nuclei-induced actin polymerization by blocking filament elongation.
复制标题
DOI：
10.1083/jcb.84.2.455
复制
发表时间：
1980-02
影响因子：
7.8
通讯作者：
Lin, S
中科院分区：
文献类型：
--
作者：
Lin, D C;Tobin, K D;Grumet, M;Lin, S
在含有0.4 mM氯化镁的低离子强度缓冲液中，发现聚赖氨酸可以诱导肌肉肌动蛋白的聚合。诱导聚合的速度取决于聚赖氨酸的加入量和分子大小。在相同条件下，将由对-N，N‘-苯双马来酰亚胺交联的肌动蛋白核(约含2-4个肌动蛋白亚基)加入G-肌动蛋白，也可获得类似的作用，提示多聚赖氨酸的作用是通过促进肌动蛋白核的形成而实现的。低浓度(10(-8)-10(-6)M)的细胞松弛素能抑制多聚赖氨酸和交联型肌动蛋白核诱导的聚合。结合实验表明，肌动蛋白细丝，而不是肌动蛋白单体，含有与[~3H]细胞松弛素B的高亲和力结合部位(每600个肌动蛋白单体一个部位)。几种细胞松弛素对这些位点的相对亲和力(由[~3H]二氢细胞松弛素B的竞争性置换决定)是：细胞松弛素D大于细胞松弛素E，大致等于二氢细胞松弛素B。本研究结果表明，细胞松弛素通过与肌动蛋白细胞核和细丝中单体加入点的高度特异的位置(即延长位置)结合来抑制细胞核诱导的肌动蛋白聚合。
Polylysine was found to induce polymerization of muscle actin in a low ionic strength buffer containing 0.4 mM MgCl2. The rate of induced polymerization was dependent on the amount and on the molecular size of the polylysine added. A similar effect was obtained by adding actin nuclei (containing about 2-4 actin subunits) cross-linked by p-N,N'- phenylenebismaleimide to G-actin under the same conditions, suggesting that the effect of polylysine is due to promotion of the formation of actin nuclei. Polymerization induced by polylysine and by cross-linked actin nuclei was inhibited by low concentrations (10(-8)-10(-6)M) of cytochalasins. Binding experiments showed that actin filaments, but not actin monomers, contained high-affinity binding sites for [3H]cytochalasin B (one site per 600 actin monomers). The relative affinity of several cytochalasins for these sites (determined by competitive displacement of [3H]dihydrocytochalasin B) was: cytochalasin D greater than cytochalasin E approximately equal to dihydrocytochalasin B. The results of this study suggest that cytochalasins inhibit nuclei-induced actin polymerization by binding to highly specific sites at the point of monomer addition, i.e., the elongation site, in actin nuclei and filaments.