High Affinity Binding of β2-Glycoprotein I to Human Endothelial Cells Is Mediated by Annexin II
| Autor: | Jing Chuan Zhang, Keying Ma, Keith R. McCrae, Ronit Simantov, Roy L. Silverstein, Katherine A. Hajjar |
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| Rok vydání: | 2000 |
| Předmět: |
Umbilical Veins
Molecular Sequence Data Annexin A5 affinity assay Biology Biochemistry Membrane Lipids Annexin Humans Beta 2-Glycoprotein I Amino Acid Sequence Binding site Beta (finance) Molecular Biology Annexin A2 Cells Cultured Phospholipids Glycoproteins Binding Sites Membrane Glycoproteins HEK 293 cells Membrane Proteins Cell Biology Molecular biology Peptide Fragments Fibronectins carbohydrates (lipids) Kinetics beta 2-Glycoprotein I biology.protein lipids (amino acids peptides and proteins) Endothelium Vascular Antibody |
| Zdroj: | Journal of Biological Chemistry. 275:15541-15548 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.275.20.15541 |
| Popis: | Beta(2)-glycoprotein I (beta(2)GPI) is an abundant plasma phospholipid-binding protein and an autoantigen in the antiphospholipid antibody syndrome. Binding of beta(2)GPI to endothelial cells targets them for activation by anti-beta(2)GPI antibodies, which circulate and are associated with thrombosis in patients with the antiphospholipid antibody syndrome. However, the binding of beta(2)GPI to endothelial cells has not been characterized and is assumed to result from association of beta(2)GPI with membrane phospholipid. Here, we characterize the binding of beta(2)GPI to endothelial cells and identify the beta(2)GPI binding site. (125)I-beta(2)GPI bound with high affinity (K(d) approximately 18 nm) to human umbilical vein endothelial cells (HUVECs). Using affinity purification, we isolated beta(2)GPI-binding proteins of approximately 78 and approximately 36 kDa from HUVECs and EAHY.926 cells. Amino acid sequences of tryptic peptides from each of these were identical to sequences within annexin II. A role for annexin II in binding of beta(2)GPI to cells was confirmed by the observations that annexin II-transfected HEK 293 cells bound approximately 10-fold more (125)I-beta(2)GPI than control cells and that anti-annexin II antibodies inhibited the binding of (125)I-beta(2)GPI to HUVECs by approximately 90%. Finally, surface plasmon resonance studies revealed high affinity binding between annexin II and beta(2)GPI. These results demonstrate that annexin II mediates the binding of beta(2)GPI to endothelial cells. |
| Databáze: | OpenAIRE |
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