Ikeda K, Kaub P A, Asada H, Uyemura K, Toya S, Shirao T
Department of Physiology, Keio University, Tokyo, Japan.
Brain Res Dev Brain Res. 1996 Feb 26;91(2):227-36. doi: 10.1016/0165-3806(95)00181-6.
The expression of drebrin A was induced in mouse fibroblasts (L cells) after transformation of cells with a vector that carried cDNA for rat drebrin A (developmentally regulated brain protein A) under the control of the promoter of the gene for metallothionein-I. When drebrin was expressed in the transformed cells (MTI-5 cells), the organization of actin filaments changed such that stress fibers were converted to a mesh-like structure. After subsequent treatment with 5 micrograms/ml cytochalasin D (a reagent that depolymerizes actin filaments), MTI-5 cells maintained their shape, while cells of a drebrin-negative cell line, MTI-11, formed retraction processes. Simultaneously, actin filaments changed into patchy dot-like aggregates in the cytoplasm of both MTI-5 and MTI-11 cells. These aggregates are known as cytoplasmic pools. In MTI-5 cells, adhesion plaques that were resistant to treatment with cytochalasin D appeared upon expression of drebrin. These adhesion plaques were immunostained with vinculin-specific antibodies, while those in MTI-11 cells were hardly immunostained. The amount of vinculin in MTI-5 cells increased in parallel with increase in the level of drebrin. These results suggest that expression of drebrin A induces changes in the assembly of actin filaments and adhesion plaques, with resultant modulation of cellular adhesion to the substratum.
用携带大鼠drebrin A（发育调控脑蛋白A）cDNA的载体转化小鼠成纤维细胞（L细胞）后，在金属硫蛋白-I基因启动子的控制下，drebrin A在细胞中得以诱导表达。当drebrin在转化细胞（MTI-5细胞）中表达时，肌动蛋白丝的组织发生变化，应力纤维转变为网状结构。在用5微克/毫升细胞松弛素D（一种使肌动蛋白丝解聚的试剂）进行后续处理后，MTI-5细胞保持其形状，而drebrin阴性细胞系MTI-11的细胞则形成收缩突起。同时，MTI-5和MTI-11细胞的细胞质中，肌动蛋白丝都转变为斑状点状聚集体。这些聚集体被称为细胞质池。在MTI-5细胞中，drebrin表达后出现了对细胞松弛素D处理有抗性的粘着斑。这些粘着斑用纽蛋白特异性抗体进行免疫染色，而MTI-11细胞中的粘着斑几乎没有被免疫染色。MTI-5细胞中纽蛋白的量随着drebrin水平的增加而平行增加。这些结果表明，drebrin A的表达诱导了肌动蛋白丝和粘着斑组装的变化，从而对细胞与基质的粘附进行调节。
