R to Q amino acid substitution in the GFFKR sequence of the cytoplasmic domain of the integrin αIIb subunit in a patient with a Glanzmann's thrombasthenia-like syndrome
R to Q amino acid substitution in the GFFKR sequence of the cytoplasmic domain of the integrin αIIb subunit in a patient with a Glanzmann's thrombasthenia-like syndrome
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DOI：
10.1182/blood.v92.11.4178.423k08_4178_4187
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发表时间：
1998-12-01
期刊：
影响因子：
20.3
通讯作者：
Bourre, F
中科院分区：
文献类型：
--
作者：
Peyruchaud, O;Nurden, AT;Bourre, F
整合素α（IIb）β（3）通过其纤维蛋白原和粘附蛋白结合特性介导血小板聚集。特别感兴趣的是α（IIb）和β（3）胞质结构域的作用。我们现在报告对一名Glanzmann血小板无力症样综合征患者的α（IIb）β（3）进行分子分析，该患者的主要特征是α（IIb）β（3）的总血小板含量约为50%，但在表面池中的比例要低得多（Hardisty等，Blood 80：696，1992），聚合酶链反应（PCR）单链构象多态性和DNA测序显示杂合突变，导致α（IIb）的胞质结构域的GFFKR序列中的氨基酸取代R-995为Q，逆转录酶-PCR和多态性分析仅检测到他的血小板中α（IIb）基因的突变等位基因和β（3）基因的单个等位基因的mRNA，表明其他未鉴定的缺陷。定点突变后，突变的α（IIb）和野生型β（3）在Cos-7细胞中瞬时表达，与野生型α（IIb）和β（3）转染的细胞相比，细胞表面复合物的表达显著降低。转染的细胞系显示突变的受体没有被锁定到高活化状态，尽管在活化抗体抗LIBS 6存在下它变得如此。这是第一个报告的自然突变的高度保守的GFFKR序列的α（IIb）胞质结构域。(C)1998年，美国血液学会。
The integrin alpha(IIb)beta(3) mediates platelet aggregation through its fibrinogen and adhesive protein-binding properties. Particular interest concerns the role of the cytoplasmic domains of alpha(IIb) and beta(3), We now report the molecular analysis of alpha(IIb)beta(3) from a patient with a Glanzmann's thrombasthenia-like syndrome for whom the principal characteristics are an approximate 50% total platelet content of alpha(IIb)beta(3) but with a much lower proportion in the surface pool (Hardisty et at, Blood 80:696, 1992), Polymerase chain reaction (PCR) single-strand conformational polymorphism and DNA sequencing showed a heterozygous mutation giving rise to amino acid substitution R-995 to Q in the GFFKR sequence of the cytoplasmic domain of alpha(IIb), Reverse transcriptase-PCR and polymorphism analysis only detected mRNA for the mutated allele of the alpha(IIb) gene and a single allele of the beta(3) gene in his platelets, suggesting other unidentified defects. Site-directed mutagenesis followed by transient expression of the mutated a(IIb) together with wild-type beta(3) in Cos-7 cells resulted in a markedly decreased expression of the complex at the cell surface when compared with cells transfected with wildtype alpha(IIb) and beta(3) Flow cytometry with PAC-1 and a stable Chinese hamster ovary-transfected cell line showed that the mutated receptor was not locked into a high activation state, although it became so in the presence of the activating antibody, anti-LIBS6. This is the first reported natural mutation in the highly conserved GFFKR sequence of the alpha(IIb) cytoplasmic domain. (C) 1998 by The American Society of Hematology.