PDF(Pubmed)
Abstract：
ADAMTS13, a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13, regulates the length of Von Willebrand factor (VWF) multimers and their platelet-binding activity. ADAMTS13 is constitutively secreted as an active protease and is not inhibited by circulating protease inhibitors. Therefore, the mechanisms that regulate ADAMTS13 protease activity are unknown. We performed an unbiased proteomics screen to identify ligands of ADAMTS13 by optimizing the application of BioID to plasma. Plasma BioID identified 5 plasma proteins significantly labeled by the ADAMTS13-birA* fusion, including VWF and plasminogen. Glu-plasminogen, Lys-plasminogen, mini-plasminogen, and apo(a) bound ADAMTS13 with high affinity, whereas micro-plasminogen did not. None of the plasminogen variants or apo(a) bound to a C-terminal truncation variant of ADAMTS13 (MDTCS). The binding of plasminogen to ADAMTS13 was attenuated by tranexamic acid or ε-aminocaproic acid, and tranexamic acid protected ADAMTS13 from plasmin degradation. These data demonstrate that plasminogen is an important ligand of ADAMTS13 in plasma by binding to the C-terminus of ADAMTS13. Plasmin proteolytically degrades ADAMTS13 in a lysine-dependent manner, which may contribute to its regulation. Adapting BioID to identify protein-interaction networks in plasma provides a powerful new tool to study protease regulation in the cardiovascular system.
摘要：
ADAMTS13，一种具有血小板反应蛋白1型基序的解整合素和金属蛋白酶，成员13调节血管性血友病因子（VWF）多聚体的长度及其血小板结合活性。ADAMTS13作为活性蛋白酶组成型分泌,并且不被循环蛋白酶抑制剂抑制。因此,调节ADAMTS13蛋白酶活性的机制尚不清楚。我们进行了无偏蛋白质组学筛选，通过优化BioID在血浆中的应用来鉴定ADAMTS13的配体。血浆BioID鉴定了由ADAMTS13-birA*融合物显著标记的5种血浆蛋白，包括VWF和纤溶酶原。Glu-纤溶酶原,Lys-纤溶酶原,微型纤溶酶原,和apo(a)以高亲和力结合ADAMTS13，而微纤溶酶原没有。纤溶酶原变体或apo(a)均不与ADAMTS13(MDTCS)的C末端截短变体结合。氨甲环酸或ε-氨基己酸减弱了纤溶酶原与ADAMTS13的结合，和氨甲环酸保护ADAMTS13免受纤溶酶降解。这些数据表明纤溶酶原通过与ADAMTS13的C末端结合而在血浆中是ADAMTS13的重要配体。纤溶酶以赖氨酸依赖性方式蛋白水解降解ADAMTS13，这可能有助于其监管。调整BioID以识别血浆中的蛋白质相互作用网络为研究心血管系统中的蛋白酶调节提供了强大的新工具。
