Structure of the platelet membrane glycoprotein IIb. Homology to the alpha subunits of the vitronectin and fibronectin membrane receptors.
Structure of the platelet membrane glycoprotein IIb. Homology to the alpha subunits of the vitronectin and fibronectin membrane receptors.
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DOI：
10.1016/s0021-9258(18)47438-8
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发表时间：
1987-06
期刊：
影响因子：
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通讯作者：
M. Poncz;R. Eisman;R. Heidenreich;S. M. Silver;G. Vilaire;S. Surrey;E. Schwartz;J. Bennett
中科院分区：
文献类型：
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作者：
M. Poncz;R. Eisman;R. Heidenreich;S. M. Silver;G. Vilaire;S. Surrey;E. Schwartz;J. Bennett
血小板膜糖蛋白IIb X IIIa异二聚体复合物（GPIIb X IIIa）是粘附蛋白的血小板受体，在活化的血小板上含有纤维蛋白原、血管性血友病因子和纤连蛋白的结合位点。GPIIb X IIIa似乎也是在细胞-细胞和细胞-基质相互作用中起主要作用的膜粘附蛋白受体家族的成员。GPIb是这种血小板受体的较大组分，由两个二硫键连接的亚基组成。在这份报告中，我们描述了人GPIIb的cDNA克隆的分析，这些克隆是从使用来自HEL细胞的RNA制备的λ gt 11表达文库中分离的。共测定了3.3个酶的cDNA序列，揭示了一个连续的开放阅读框架，编码两个GPIIb亚基。cDNA编码1039个氨基酸：137个构成较小的亚基，871个构成较大的亚基，30个构成NH 2-末端信号肽。大小亚基之间没有发现同源性。较小的亚基在其COOH末端附近含有26个残基的疏水序列，其代表潜在的跨膜结构域。存在于较大亚基中的4段12个氨基酸与钙调蛋白和肌钙蛋白C的钙结合位点同源。使用HEL细胞RNA的北方印迹分析表明，编码GPIIb的成熟mRNA的大小为4.1个酶。GPIIb编码区与玻连蛋白和纤连蛋白受体α-链的cDNA序列的比较分别显示41%的DNA同源性和74%和63%的氨基酸同源性。我们的数据建立了人血小板糖蛋白IIb的氨基酸序列，并提供了细胞粘附蛋白受体家族存在的额外证据。
The platelet membrane glycoprotein IIb X IIIa heterodimer complex (GPIIb X IIIa) is the platelet receptor for adhesive proteins, containing binding sites for fibrinogen, von Willebrand factor, and fibronectin on activated platelets. GPIIb X IIIa also appears to be a member of a family of membrane adhesive protein receptors that plays a major role in cell-cell and cell-matrix interactions. GPIb is the larger component of this platelet receptor and is composed of two disulfide-linked subunits. In this report we describe the analysis of cDNA clones for human GPIIb that were isolated from a lambda gt11 expression library prepared using RNA from HEL cells. A total of 3.3 kilobases of cDNA was sequence, revealing a continuous open reading frame encoding both GPIIb subunits. The cDNA encodes 1039 amino acids: 137 constituting the smaller subunit, 871 constituting the larger subunit, and 30 constituting an NH2-terminal signal peptide. No homology was found between the larger and smaller subunits. The smaller subunit contains a 26-residue hydrophobic sequence near its COOH terminus that represents a potential transmembrane domain. Four stretches of 12 amino acids present in the larger subunit are homologous to the calcium binding sites of calmodulin and troponin C. Northern blot analysis using HEL cell RNA indicated that the mature mRNA coding for GPIIb is 4.1 kilobases in size. A comparison of the GPIIb coding region with available cDNA sequences of the alpha-chains of the vitronectin and fibronectin receptors revealed 41% DNA homology and 74% and 63% amino acid homology, respectively. Our data establish the amino acid sequence for the human platelet glycoprotein IIb and provide additional evidence for the existence of a family of cellular adhesion protein receptors.