Arpin M, Pringault E, Finidori J, Garcia A, Jeltsch J M, Vandekerckhove J, Louvard D
Institut Pasteur, Département de Biologie Moléculaire, Paris, France.
J Cell Biol. 1988 Nov;107(5):1759-66. doi: 10.1083/jcb.107.5.1759.
Villin is a calcium-regulated actin-binding protein that caps, severs, and bundles actin filaments in vitro. This 92,500-D protein is a major constituent of the actin bundles within the microvilli of the brush border surface of intestinal and kidney proximal tubule cells. Villin is a very early marker of cells involved in absorption and its expression is highly increased during intestinal cell differentiation. The amino acid sequence deduced from the cDNA sequence revealed that human villin is composed of three domains. The first two domains appear as the result of a duplication: their structural organization is similar. We can then define a basic unit in which a slightly hydrophilic motif is followed by three hydrophobic motifs, similar between themselves and regularly spaced. The duplicated domain is highly homologous to three other actin-severing proteins and this basic structure represents the whole molecule in severin and fragmin, while two basic units compose gelsolin. The third domain which is carboxy terminal is villin specific: it is unique among actin modulating proteins so far known. It could account for its actin-binding properties (dual regulation by calcium of severing and bundling activities). We propose that it may also be related to the subcellular localization of villin in different epithelial cell types.
绒毛蛋白是一种受钙调节的肌动蛋白结合蛋白，在体外可封闭、切断并捆绑肌动蛋白丝。这种92,500道尔顿的蛋白质是肠道和肾近端小管细胞刷状缘表面微绒毛内肌动蛋白束的主要成分。绒毛蛋白是参与吸收的细胞的一个非常早期的标志物，其表达在肠道细胞分化过程中高度增加。从cDNA序列推导的氨基酸序列显示，人绒毛蛋白由三个结构域组成。前两个结构域是重复的结果：它们的结构组织相似。然后我们可以定义一个基本单元，其中一个略带亲水性的基序后面跟着三个疏水性基序，它们彼此相似且间隔规则。重复的结构域与其他三种肌动蛋白切断蛋白高度同源，这种基本结构在肌动蛋白切断蛋白和凝溶胶蛋白中代表整个分子，而凝溶胶蛋白由两个基本单元组成。第三个结构域位于羧基末端，是绒毛蛋白特有的：在目前已知的肌动蛋白调节蛋白中它是独一无二的。它可以解释其肌动蛋白结合特性（切断和捆绑活性受钙的双重调节）。我们提出，它也可能与绒毛蛋白在不同上皮细胞类型中的亚细胞定位有关。
