Physical and functional interaction between cell-surface calreticulin and the collagen receptors integrin α2β1 and glycoprotein VI in human platelets
Physical and functional interaction between cell-surface calreticulin and the collagen receptors integrin α2β1 and glycoprotein VI in human platelets
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DOI：
10.1055/s-0037-1613270
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发表时间：
2002-10-01
影响因子：
6.7
通讯作者：
Farndale, RW
中科院分区：
文献类型：
--
作者：
Elton, CM;Smethurst, PA;Farndale, RW
钙网蛋白是大多数细胞内质网中丰富的蛋白质。在这项研究中，流式细胞术和免疫沉淀从表面生物素化血小板各自提供了直接的证据，钙网蛋白也表达在人类血小板的表面。抗钙网蛋白抗体引起血小板活化，诱导Fc γ RIIa非依赖性血小板聚集。此外，这些抗体抑制血小板与整合素α 2 β 1特异性配体GFOGER-GPP和单体胶原I以及与糖蛋白VI特异性配体CRP的粘附。抑制血小板粘附这些配体是独立的整合素α IIb β 3。在静息血小板中，钙网蛋白与整合素α 2 β 1和糖蛋白VI相互作用。总之，这些数据表明，表面钙网蛋白与血小板表面上的胶原蛋白受体相关，在那里它可能在血小板-胶原蛋白相互作用的调节中发挥作用。
Calreticulin is an abundant protein in the endoplasmic reticulum of most cells. In this study, flow cytometry and, immunoprecipitation from surface-biotinylated platelets each provided direct evidence that calreticulin is also expressed on the surface of human platelets. Anti-calreticulin antibodies caused platelet activation, inducing FcgammaRIIa-independent platelet aggregation. In addition, these antibodies inhibited platelet adhesion to the integrin alpha2beta1-specific ligands, GFOGER-GPP and monomeric collagen I, and to the glycoprotein VI-specific ligand, CRP. Inhibition of platelet adhesion to these ligands was independent of integrin alphaIIbbeta3. In resting platelets, calreticulin was shown to interact with integrin alpha2beta1 and glycoprotein VI. Together, these data demonstrate that surface calreticulin is associated with collagen receptors on the platelet surface, where it may play a role in the modulation of the platelet-collagen interaction.