Characterization of extracellular binding sites for [3H]-staurosporine on capillary endothelial cells.
[3H]-staurosporine, a non-specific protein kinase inhibitor, bound with high affinity and in a reversible manner to specific and saturable binding sites in cultured bovine cerebral cortex capillary endothelial cells. Scatchard analysis revealed the presence of one class of non-interacting binding sites with an equilibrium dissociation constant (KD) of 9.2 nM and Bmax of 19.3 fmol/10(5) cells. The binding of [3H]-staurosporine was fully displaced by unlabelled staurosporine, H-7 and ATP with IC50 values of 6.9 nM, 3 microM and 0.4 microM respectively. Mild trypsinization of cells after [3H]-staurosporine binding revealed the presence of membrane-associated, extracellular binding sites which could be an ecto-protein kinase.
Herbert
J M
JM
Haemobiology research department, Sanofi Recherche, Toulouse, France.
Daviet
I
I
Maffrand
J P
JP
D000470:Alkaloids / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D001921:Brain / Q000098:blood supply; D002196:Capillaries / Q000737:chemistry; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured / Q000737:chemistry; D004730:Endothelium, Vascular / Q000737:chemistry / Q000378:metabolism*; D019311:Staurosporine
D000470:Alkaloids; D019311:Staurosporine