Variability in the expression of urokinase receptor (CD87) mutants on cells: relevance to cell adhesion

Cell Biochemistry and Function
Sandip M KanseKlaus T Preissner

Abstract

The urokinase-type plasminogen activator receptor (uPAR, CD87) is a glycosylphosphatidylinositol (GPI)-anchored protein, containing three homologous Ly-6 domains, that mediates integrin-independent cell adhesion by directly binding to extracellular matrix protein vitronectin (VN). To elucidate the structural requirements for the uPAR-dependent cell adhesion on VN, several glycolipid-anchored variants of uPAR were expressed in BAF3 cells, (mouse pre B-lymphocytes) followed by functional analysis. The individual domains of uPAR were expressed at very low levels, the two domain mutants were expressed to a higher level and the wild type uPAR was expressed highly. Point mutations in domain 2 of uPAR have been shown to diminish cellular binding of the ligand urokinase and we observed a lack of VN binding to this mutant. Flow cytometry with a number of monoclonal antibodies indicated that the domain-specific antigenic determinants in these mutants were well preserved. Only the cells expressing the intact uPAR with all three domains adhered strongly to a VN substrate, whereas none of the other transfected cells showed significant cell adhesion. Hence, any alterations in the domain structure of uPAR reduce its expression and only the in...Continue Reading

Citations

Aug 6, 2005·Proceedings of the National Academy of Sciences of the United States of America·Pilar BlancafortCarlos F Barbas

❮ Previous
Next ❯

Related Concepts

Related Feeds

Adhesion Molecules in Health and Disease

Cell adhesion molecules are a subset of cell adhesion proteins located on the cell surface involved in binding with other cells or with the extracellular matrix in the process called cell adhesion. In essence, cell adhesion molecules help cells stick to each other and to their surroundings. Cell adhesion is a crucial component in maintaining tissue structure and function. Discover the latest research on adhesion molecule and their role in health and disease here.