Structural Basis for Recognition of Urokinase-type Plasminogen Activator by Plasminogen Activator Inhibitor-1
Structural Basis for Recognition of Urokinase-type Plasminogen Activator by Plasminogen Activator Inhibitor-1
复制标题
纤溶酶原激活剂抑制剂-1识别尿激酶型纤溶酶原激活剂的结构基础
DOI：
10.1074/jbc.m110.204537
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发表时间：
2011-03-04
影响因子：
4.8
通讯作者：
Huang, Mingdong
中科院分区：
文献类型：
--
作者：
Lin, Zhonghui;Jiang, Longguang;Huang, Mingdong
纤溶酶原激活物抑制剂-1（派-1）与其生理靶点尿激酶型纤溶酶原激活物（uPA）一起在纤维蛋白溶解、细胞迁移和组织重塑中起关键作用，并且目前被认为是几种癌症类型中最广泛验证的生物学预后因子之一。派-1特异性且快速地抑制uPA和组织型PA（tPA）。尽管对这两种反应进行了广泛的结构/功能研究，但由于获得相关结构的技术困难，潜在的结构机制仍然未知。在这里，我们报告了一种策略，以产生派-1.uPA（S195 A）米氏复合物，并提出其晶体结构在2.3埃分辨率。在这种结构中，派-1反应中心环作为诱饵将uPA吸引到派-1分子的顶部。反应中心环的P4-P3'残基与uPA催化位点广泛相互作用，约占总接触面积的三分之二。除了活性位点外，几乎所有的uPA外位点环，包括37-、60-、97-、147-和217-环，都参与与派-1的相互作用。uPA 37-环与派-1 β-折叠B广泛相互作用，147-环直接接触派-1 β-折叠C。这两个环是重要的初始米氏络合物的形成。本研究为了解派-1对uPA和tPA的特异性奠定了基础，并为进一步的功能研究提供了结构基础。
Plasminogen activator inhibitor-1 (PAI-1), together with its physiological target urokinase-type plasminogen activator (uPA), plays a pivotal role in fibrinolysis, cell migration, and tissue remodeling and is currently recognized as being among the most extensively validated biological prognostic factors in several cancer types. PAI-1 specifically and rapidly inhibits uPA and tissue-type PA (tPA). Despite extensive structural/functional studies on these two reactions, the underlying structural mechanism has remained unknown due to the technical difficulties of obtaining the relevant structures. Here, we report a strategy to generate a PAI-1.uPA(S195A) Michaelis complex and present its crystal structure at 2.3-angstrom resolution. In this structure, the PAI-1 reactive center loop serves as a bait to attract uPA onto the top of the PAI-1 molecule. The P4-P3' residues of the reactive center loop interact extensively with the uPA catalytic site, accounting for about two-thirds of the total contact area. Besides the active site, almost all uPA exosite loops, including the 37-, 60-, 97-, 147-, and 217-loops, are involved in the interaction with PAI-1. The uPA 37-loop makes an extensive interaction with PAI-1 beta-sheet B, and the 147-loop directly contacts PAI-1 beta-sheet C. Both loops are important for initial Michaelis complex formation. This study lays down a foundation for understanding the specificity of PAI-1 for uPA and tPA and provides a structural basis for further functional studies.