Ero1α Is Expressed on Blood Platelets in Association with Protein-disulfide Isomerase and Contributes to Redox-controlled Remodeling of αIIbβ3
Ero1α Is Expressed on Blood Platelets in Association with Protein-disulfide Isomerase and Contributes to Redox-controlled Remodeling of αIIbβ3
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DOI：
10.1074/jbc.m109.092486
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发表时间：
2010-09-24
影响因子：
4.8
通讯作者：
Cierniewski, Czeslaw S.
中科院分区：
文献类型：
--
作者：
Swiatkowska, Maria;Padula, Gianluca;Cierniewski, Czeslaw S.
最近的证据支持蛋白质二硫键异构酶（PDI）在血小板中α（IIb）β（3）的外表面结构域的氧化还原控制重塑中的作用。本研究的目的是解释Ero 1 α是否可以负责细胞外再氧化的PDI活性位点。我们发现Ero 1 α可以在血小板上发现，并在血小板激动剂的作用下迅速募集到细胞表面。它与PDI和α（IIb）β（3）物理相关，如共聚焦显微镜共定位分析所示，并通过免疫沉淀实验证实。除单体氧化Ero 1 α外，抗α（IIb）β（3）免疫沉淀物显示存在几条Ero 1 α阳性条带，对应于复合物α（IIb）β（3）-PDI-Ero 1 α、PDI-Ero 1 α和Ero 1 α-Ero 1 α二聚体。它能更有效地与活化的α（IIb）β（3）构象异构体结合，其相互作用被RGD肽抑制。Ero 1 α似乎参与α（IIb）β（3）受体活性的调节，原因如下：（a）通过抗体阻断细胞表面Ero 1 α导致响应激动剂的血小板聚集减少以及纤维蛋白原和PAC-1结合减少，和（B）用Ero 1 α转染MEG 01增加α（II B）β（3）受体活性，如纤维蛋白原结合增加所示。
Recent evidence supports a role of protein-disulfide isomerase (PDI) in redox-controlled remodeling of the exofacial domains of alpha(IIb)beta(3) in blood platelets. The aim of this study was to explain whether Ero1 alpha can be responsible for extracellular reoxidation of the PDI active site. We showed that Ero1 alpha can be found on platelets and is rapidly recruited to the cell surface in response to platelet agonists. It is physically associated with PDI and alpha(IIb)beta(3), as suggested by colocalization analysis in confocal microscopy and confirmed by immunoprecipitation experiments. Apart from monomeric oxidized Ero1 alpha, anti-alpha(IIb)beta(3) immunoprecipitates showed the presence of several Ero1 alpha-positive bands that corresponded to the complexes alpha(IIb)beta(3)-PDI-Ero1 alpha, PDI-Ero1 alpha, and Ero1 alpha-Ero1 alpha dimers. It binds more efficiently to the activated alpha(IIb)beta(3) conformer, and its interaction is inhibited by RGD peptides. Ero1 alpha appears to be involved in the regulation of alpha(IIb)beta(3) receptor activity because of the following: (a) blocking the cell surface Ero1 alpha by antibodies leads to a decrease in platelet aggregation in response to agonists and a decrease in fibrinogen and PAC-1 binding, and (b) transfection of MEG01 with Ero1 alpha increases alpha(IIb)beta(3) receptor activity, as indicated by increased binding of fibrinogen.