Human melanoma cells express a novel integrin receptor for laminin.
Human melanoma cells express a novel integrin receptor for laminin.
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发表时间：
1989-09
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通讯作者：
R. Kramer;K. Mcdonald;M. Vu
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作者：
R. Kramer;K. Mcdonald;M. Vu
这项研究试图确定人类黑色素瘤细胞是否表达与整合素相关的受体，以介导其与层粘连蛋白的黏附。我们发现，针对整合素β1链的抗体阻止了细胞与层粘连蛋白涂层表面的附着。此外，免疫荧光染色显示，在附着于层粘连蛋白底物的细胞基面上，纽蛋白阳性的局灶性黏附斑块中有β1复合体。125I标记细胞的洗涤剂提取物在层粘连蛋白-琼脂糖柱上层析，得到两个主要的层粘连蛋白结合蛋白(100和130 kDa，还原)，它们与柱子高亲和力结合，并用EDTA洗脱。这两种蛋白都是用整合素β1亚基的单抗和多克隆抗体从柱级分中特异性地免疫沉淀的，表明它们形成了非共价的异二聚体复合体。类阿尔法亚基由一个30 kDa的轻链组成，该轻链通过二硫键连接到100 kDa的重链上。这种复合体不是从纤维连接蛋白或I型或IV型琼脂糖柱中回收的。层粘连蛋白与α-β1复合体的结合独立于Arg-Gly-Asp或Tyr-Ile-Gly-Ser-Arg-like序列，但需要二价阳离子的存在。100 kDa的类α亚基在电泳学和免疫化学上与其他已知的α亚基-α1-α6不同。结果表明，人黑色素瘤细胞表达一种新的层粘连蛋白特异性整合素β1复合体，该复合体可能介导细胞与该配体的相互作用。
This study sought to determine whether human melanoma cells express integrin-related receptors that mediate their adhesion to laminin. We found that antibodies against the integrin beta 1 chain blocked cell attachment to laminin-coated surfaces. Furthermore, immunofluorescence staining demonstrated beta 1 complexes in vinculin-positive focal adhesion plaques on the basal surface of cells attached to laminin substrates. Chromatography of detergent extracts of 125I-surface-labeled cells on laminin-Sepharose columns recovered two major laminin-binding proteins (100 and 130 kDa, reduced) that bound with high affinity to the columns and were eluted with EDTA. Both proteins were specifically immunoprecipitated from column fractions with monoclonal and polyclonal antibodies to the integrin beta 1 subunit, indicating that they form a noncovalent heterodimer complex. The alpha-like subunit is composed of a 30-kDa light chain that is joined by a disulfide bond to the 100-kDa heavy chain. This complex was not recovered from columns of fibronectin- or collagen type I- or IV-Sepharose. Laminin-binding by the alpha beta 1 complex was independent of Arg-Gly-Asp or Tyr-Ile-Gly-Ser-Arg-like sequences, but required the presence of divalent cations. The 100-kDa alpha-like subunit was electrophoretically and immunochemically distinct from the other known alpha subunits, alpha 1-alpha 6. The results indicate that human melanoma cells express a novel laminin-specific integrin beta 1 complex which may mediate the cells' interactions with this ligand.