TISSUE PLASMINOGEN ACTIVATOR BINDING TO ANNEXIN II TAIL DOMAIN DIRECT MODULATION

组织型纤溶酶原激活剂通过 钙调节磷脂结合蛋白Annexin II，And 被血栓前氨基酸抑制的相互作用 同型半胱氨酸。我们试图鉴定组织型纤溶酶原激活剂 膜联蛋白II的结合域及其作用机制的研究 同型半胱氨酸的调节作用。组织型纤溶酶原激活剂与 固定化膜联蛋白II被完整液相膜联蛋白II抑制 但不是通过它的“核心”片段(残基25-339)。两个重叠 “尾部”多肽特别阻止了65%-75%的结合。本土化 组织纤溶酶原激活物结合结构域的 六肽LCKLSL(残基7-12)的特异性抑制作用。 表达的C9G膜联蛋白II蛋白不支持组织型纤溶酶原 激活剂结合，而与C133G、C262G和C335G结合 相当于野生型膜联蛋白II.暴露于 同型半胱氨酸，膜联蛋白II的质量增加了135+/-4-Da 特异性定位于Cys9，组织损失60%-66% 纤溶酶原激活物结合能力。在处理培养的 内皮细胞与二硫苏糖醇敏感的[35S]同型半胱氨酸 用抗Annexin II抗体免疫沉淀回收标记。 这些数据为血栓前反应提供了一个潜在的机制。 通过证明组织直接阻断同型半胱氨酸 膜联蛋白的纤溶酶原激活物结合域II.Hajjar，K.A.， 首页--期刊主要分类--期刊细介绍--期刊题录与文摘--期刊详细文摘内容 B.T.J.Biol.化学。1998年4月17日273(16)9987-9993

Tissue plasminogen activator binds to endothelial cells via the calcium-regulated phospholipid-binding protein annexin II, an interaction that is inhibited by the prothrombotic amino acid homocysteine. We sought to identify the tissue plasminogen activator binding domain of annexin II and to determine the mechanism of its modulation by homocysteine. Tissue plasminogen activator binding to immobilized annexin II was inhibited by intact fluid phase annexin II but not by its "core" fragment (residues 25-339). Two overlapping "tail" peptides specifically blocked 65-75% of binding. Localization of the tissue plasminogen activator binding domain was confirmed upon specific inhibition by the hexapeptide LCKLSL (residues 7-12). Expressed C9G annexin II protein failed to support tissue plasminogen activator binding, while binding to C133G, C262G, and C335G was equivalent to that of wild type annexin II. Upon exposure to homocysteine, annexin II underwent a 135 +/- 4-Da increase in mass localizing specifically to Cys9 and a 60-66% loss in tissue plasminogen activator-binding capacity. Upon treatment of cultured endothelial cells with [35S]homocysteine, the dithiothreitol-sensitive label was recovered by immunoprecipitation with anti-annexin II IgG. These data provide a potential mechanism for the prothrombotic effect of homocysteine by demonstrating direct blockade of the tissue plasminogen activator binding domain of annexin II. Hajjar, K.A., Mauri, L. Jacovina, A.T. Zhong, F., Mirza U.A., Padovan, J.C., Chait, B.T. J. Biol. Chem. 1998, Apr 17 273(16) 9987-9993,