Department of Biological and Medical Chemistry, Faculty of Fundamental Medicine, Moscow State University, Lomonosovsky pr, 31-5, Moscow 119192, Russia.
Biochem Biophys Res Commun. 2010 Jun 25;397(2):277-82. doi: 10.1016/j.bbrc.2010.05.100. Epub 2010 May 24.
Urokinase receptor (uPAR) associates in cis with complement receptor 3 (CR3). In the present study, we addressed whether this coupling regulates CR3-mediated phagocytosis. CR3-mediated attachment of iC3b-opsonized sheep red blood cells to human neutrophils and internalization of these cells were reduced by removal of cell-bound uPAR by phosphatidylinositol-specific phospholipase C and reconstituted in the presence of soluble uPAR. The attachment and internalization were suppressed in the presence of anti-uPAR polyclonal antibody, proteolytically inactive urokinase and saccharides that disrupt interaction of uPAR with CR3. Thus, uPAR acts as a cofactor for iC3b binding to CR3 and regulates CR3-mediated phagocytosis.
尿激酶受体 (uPAR) 在顺式上与补体受体 3 (CR3) 相关联。在本研究中，我们探讨了这种偶联是否调节 CR3 介导的吞噬作用。通过磷脂酰肌醇特异性磷脂酶 C 去除细胞结合的 uPAR，可以减少 CR3 介导的 iC3b 调理的绵羊红细胞与人嗜中性粒细胞的附着和这些细胞的内化，并且在存在可溶性 uPAR 的情况下可以重建。附着和内化在存在抗 uPAR 多克隆抗体、蛋白水解失活尿激酶和破坏 uPAR 与 CR3 相互作用的糖的情况下受到抑制。因此，uPAR 作为 iC3b 与 CR3 结合的辅助因子起作用，并调节 CR3 介导的吞噬作用。
