SPECTRIN-ACTIN ASSOCIATIONS STUDIED BY ELECTRON-MICROSCOPY OF SHADOWED PREPARATIONS
SPECTRIN-ACTIN ASSOCIATIONS STUDIED BY ELECTRON-MICROSCOPY OF SHADOWED PREPARATIONS
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DOI：
10.1016/0092-8674(80)90451-1
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发表时间：
1980-01-01
期刊：
影响因子：
64.5
通讯作者：
BRANTON, D
中科院分区：
文献类型：
--
作者：
COHEN, CM;TYLER, JM;BRANTON, D
通过将干燥的标本置于云母片上，获得了由血影蛋白（一种在红细胞中发现的肌动蛋白结合蛋白）交联的肌动蛋白的清晰图像。Spectrin二聚体具有F肌动蛋白的单一结合位点。由2个二聚体的头对头缔合形成的四聚体具有2个肌动蛋白结合位点，每个尾部1个。在血影蛋白四聚体存在下聚合G肌动蛋白或将预先形成的F肌动蛋白与血影蛋白四聚体加带4.1混合，导致肌动蛋白丝的广泛交联网络。当G肌动蛋白在血影蛋白：肌动蛋白摩尔比接近红细胞膜上存在的血影蛋白的存在下聚合时，形成大的无定形蛋白质网络。这些网络是直径约25 nm的血影蛋白簇，可能是肌动蛋白原丝。这些网络是类似的细胞骨架网络后，红细胞膜用洗涤剂提取，并可能代表第一次在体外组装的细胞骨架复合物类似的天然细胞的生化和结构。
By shadowing specimens dried onto mica sheets, clear images of actin crosslinked by spectrin, an actin-binding protein found in erythrocytes, were obtained. Spectrin dimers possess a single binding site for F actin. Tetramers formed by head-to-head association of 2 dimers possess 2 actin binding sites, 1 at each tail. Polymerizing G actin in the presence of spectrin tetramers or mixing preformed F actin with spectrin tetramer plus band 4.1 results in an extensively crosslinked network of actin filaments. When G actin is polymerized in the presence of spectrin at spectrin:actin mole ratios close to that present on the erythrocyte membrane, large amorphous protein networks are formed. These networks are clusters of spectrin around 25 nm diameter structures which may be actin protofilaments. These networks are similar to the cytoskeletal network seen after erythrocyte membranes are extracted with detergent, and may represent the first in vitro assembly of a cytoskeletal complex resembling that of the native cell both biochemically and structurally.