Regulation of CD11b/CD18 (Mac-1) adhesion to fibrinogen by urokinase receptor (uPAR)
1The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, 3400 North Broad Street, Philadelphia, PA 19140, USA.
Objective And Design:
The goal of this study is to investigate the consequence of the interaction between Mac-1 and uPAR and determine the mechanisms by which uPAR regulates Mac-1 dependent adhesion to fibrinogen.
Material:
Human embryonic kidney 293 cells transfected with Mac-1 or uPAR or co-transfected with both Mac-1 and uPAR.
Methods:
Cell adhesion and binding assays and Western Blotting for protein tyrosine phosphorylation analysis.
Results:
The adhesion to fibrinogen was increased two-fold for Mac-1-uPAR co-transfected cells comparing to the Mac-1 transfected cells alone. The increased adhesion was inhibited when cells were treated with phosphatidylinositol-specific phospholipase C to remove uPAR. Occupancy of uPAR with urokinase-type plasminogen activator further enhanced the cell adhesion to fibrinogen. Phosphorylation of focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) was increased in Mac-1-uPAR co-transfected cells but not in Mac-1 transfected cells.
Conclusions:
uPAR up-regulated the Mac-1 adhesion to fibrinogen and FAK and MAPK were involved in this regulation.
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