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Identification of an endothelial cell surface protein that binds plasminogen
A K Dudani1, S Hashemi, M T Aye
1Ottawa Blood Centre, Canadian Red Cross Society, Ontario.
Molecular and Cellular Biochemistry
|December 11, 1991
Summary
Researchers identified a 45 kDa cell-surface protein on human endothelial cells that acts as a major receptor for plasminogen binding. This finding is crucial for understanding plasminogen interactions in endothelial cells.
Area of Science:
- Biochemistry
- Cell Biology
- Vascular Biology
Background:
- Endothelial cells play a critical role in vascular homeostasis.
- Plasminogen, a key protein in fibrinolysis, interacts with endothelial cells.
- Identifying endothelial plasminogen-binding components is essential for understanding vascular function.
Purpose of the Study:
- To identify and characterize endothelial cell surface components that bind plasminogen.
- To determine the molecular nature and localization of plasminogen receptors on human endothelial cells.
Main Methods:
- Ligand-blotting assays using labeled glu-plasminogen and lys-plasminogen.
- Analysis of binding specificity and reversibility with lysine and unlabeled plasminogen.
- Proteinase K treatment and membrane fraction studies to confirm cell-surface localization.
Main Results:
- A 45 kDa endothelial cell polypeptide was identified as the primary binding component for glu-plasminogen.
- Binding was specific, reversible, and sensitive to proteinase K, confirming cell-surface localization.
- Lys-plasminogen also bound specifically to the 45 kDa protein and could displace glu-plasminogen.
Conclusions:
- The 45 kDa protein is proposed as a major receptor for plasminogen on human endothelial cells.
- This receptor mediates specific and reversible binding of plasminogen to the endothelial cell surface.
- Understanding this interaction is vital for research in thrombosis, inflammation, and angiogenesis.