Ezrin contains cytoskeleton and membrane binding domains accounting for its proposed role as a membrane-cytoskeletal linker.
Ezrin contains cytoskeleton and membrane binding domains accounting for its proposed role as a membrane-cytoskeletal linker.
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DOI：
10.1083/jcb.120.1.129
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发表时间：
1993-01
期刊：
影响因子：
--
通讯作者：
Arpin M
中科院分区：
文献类型：
--
作者：
Algrain M;Turunen O;Vaheri A;Louvard D;Arpin M
Ezrin是一种广泛存在于含有肌动蛋白的细胞表面结构中的蛋白质，是一些蛋白酪氨酸激酶的底物。基于其一级和二级结构与talin和条带4.1的相似性，有人认为该蛋白可能在连接细胞骨架和质膜方面发挥作用（Gould, k.l., a . Bretscher， F.S. Esch, and T. Hunter. 1989）。EMBO(欧元。摩尔。杂志。风琴)，J. 8:4133-4142；Turunen， O.， R. Winqvist， R. Pakkanen， K.-H。Grzeschik， T. Wahlstrom和A. Vaheri. 1989。生物。化学。264:16727- 16732)。为了验证这一假设，我们在CV-1细胞中短暂表达了完整的人ezrin cDNA，或编码蛋白质氨基和羧基末端结构域的截短cDNA。蛋白表位标记用于明确确定转染cDNA编码的蛋白的亚细胞分布。我们发现，在所有含有肌动蛋白的结构中，这种蛋白质集中在背质膜下，并且部分不溶于洗涤剂。氨基末端结构域显示相同的定位，但很容易被非离子洗涤剂提取。羧基末端结构域与微绒毛肌动蛋白丝和应力纤维共定位，在洗涤剂提取后仍与肌动蛋白丝相关，在细胞松弛素D处理后仍与无组织的肌动蛋白结构相关。我们的研究结果清楚地表明，ezrin通过其氨基末端结构域与膜相关成分相互作用，并通过其羧基末端结构域与细胞骨架相互作用。氨基末端结构域可能包括将整个蛋白限制在与背质膜接触的皮质细胞骨架及其专门的微结构域（如微绒毛、微穗和板足）的主要决定因素。
Ezrin, a widespread protein present in actin-containing cell-surface structures, is a substrate of some protein tyrosine kinases. Based on its primary and secondary structure similarities with talin and band 4.1 it has been suggested that this protein could play a role in linking the cytoskeleton to the plasma membrane (Gould, K.L., A. Bretscher, F.S. Esch, and T. Hunter. 1989. EMBO (Eur. Mol. Biol. Organ.), J. 8:4133-4142; Turunen, O., R. Winqvist, R. Pakkanen, K.-H. Grzeschik, T. Wahlstrom, and A. Vaheri. 1989. J. Biol. Chem. 264:16727- 16732). To test this hypothesis, we transiently expressed the complete human ezrin cDNA, or truncated cDNAs encoding the amino- and carboxy- terminal domains of the protein, in CV-1 cells. Protein epitope tagging was used to unambiguously determine the subcellular distribution of the protein encoded by the transfected cDNA. We show that this protein is concentrated underneath the dorsal plasma membrane in all actin- containing structures and is partially detergent insoluble. The amino- terminal domain displays the same localization but is readily extractable by nonionic detergent. The carboxy-terminal domain colocalizes with microvillar actin filaments as well as with stress fibers and remains associated with actin filaments after detergent extraction, and with disorganized actin structures after cytochalasin D treatment. Our results clearly demonstrate that ezrin interacts with membrane-associated components via its amino-terminal domain, and with the cytoskeleton via its carboxy-terminal domain. The amino-terminal domain could include the main determinant that restricts the entire protein to the cortical cytoskeleton in contact with the dorsal plasma membrane and its specialized microdomains such as microvilli, microspikes and lamellipodia.