Urokinase-dependent human vascular smooth muscle cell adhesion requires selective vitronectin phosphorylation by ectoprotein kinase CK2.
Urokinase (uPA)- and urokinase receptor (uPAR)-dependent cell adhesion to the extracellular matrix protein vitronectin (Vn) is an important event in wound healing, tissue remodeling, immune response, and cancer. We recently demonstrated that in human vascular smooth muscle cells (VSMC) uPA/uPAR are functionally associated with the ectoprotein kinase casein kinase-2 (CK2). We now asked whether CK2 regulates uPA-dependent cell adhesion to Vn, since the latter is a natural CK2 substrate. We found that Vn is indeed selectively phosphorylated by CK2 and that this phosphorylation is uPA-regulated in VSMC. Vn induces release of ecto-CK2 from the cell surface via a process termed as "shedding." CK2-mediated Vn phosphorylation was decisive for the uPA-dependent VSMC adhesion. Specific inhibition of CK2 completely abolished the uPA-induced cell adhesion to Vn. This effect was specific for cell adhesion to Vn and required participation of both uPAR and alpha(v)beta(3) integrins as adhesion receptors. CK2 localization at the cell surface was highly dynamic; Vn induced formation of clusters where CK2 colocalized with uPAR and alpha(v)beta(3) integrins. These results indicate that the uPA-dependent VSMC adhesion is a function of selective Vn phosphorylation by the ectoprotein kinase CK2 and suggest a regulatory role for Vn phosphorylation in the uPA-directed adhesive process.
Stepanova
Victoria
V
Medical Faculty of the Charité, Franz Volhard Clinic and Max Delbrück Center for Molecular Medicine, Humboldt University of Berlin, Wiltbergstrasse 50, 13125 Berlin-Buch, Germany.
Jerke
Uwe
U
Sagach
Victoriya
V
Lindschau
Carsten
C
Dietz
Rainer
R
Haller
Hermann
H
Dumler
Inna
I
D047390:Casein Kinase II; D002448:Cell Adhesion; D002460:Cell Line; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000378:metabolism; D055293:Receptors, Urokinase Plasminogen Activator; D019030:Receptors, Vitronectin / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*; D019096:Vitronectin / Q000378:metabolism*
C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D019030:Receptors, Vitronectin; D019096:Vitronectin; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D014568:Urokinase-Type Plasminogen Activator