Endothelial cell-dependent phosphorylation of a platelet protein mediated by cAMP- and cGMP-elevating factors

• Published in: The Journal of biological chemistry 1991-08, Vol.266 (22), p.14808-14812
• Main Authors: NOLTE, C, EIGENTHALER, M, SCHANZENBACHER, P, WALTER, U
• Format: Article
• Language: English
• Subjects: Autoradiography; Biological and medical sciences; Biological Factors - metabolism; Blood Platelets - metabolism; Blood Proteins - metabolism; Blotting, Western; Cell interactions, adhesion; Cells, Cultured; cyclic AMP; Cyclic AMP - metabolism; cyclic GMP; Cyclic GMP - metabolism; Endothelium, Vascular - cytology; Endothelium, Vascular - metabolism; Epoprostenol - metabolism; Fundamental and applied biological sciences. Psychology; Humans; membrane proteins; Molecular and cellular biology; Nitric Oxide - metabolism; Phosphoproteins - metabolism; Phosphorylation
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)98757-0

We reported previously that a 46/50-kDa membrane-associated vasodilator-stimulated phosphoprotein (VASP) is phosphorylated in intact human platelets in response to both cGMP- and cAMP-elevating vasodilator drugs and presented evidence that this is mediated by cGMP- and cAMP-dependent protein kinases, respectively. VASP was recently purified and an antibody against it was developed which detects a phosphorylation-induced mobility change of VASP in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Halbrügge, M., Friedrich, C., Eigenthaler, M., Schanzenbächer, P., and Walter, U. (1990) J. Biol. Chem. 265, 3088-3093). We have now used these methods for the quantitative analysis of VASP phosphorylation during coincubations of human endothelial cells and human platelets. Endothelial cell-derived factors caused the rapid, stoichiometric, and reversible phosphorylation of platelet VASP during these coincubations. Other experiments indicated that the endothelium-derived factors which stimulate VASP phosphorylation are prostacyclin and endothelium-derived relaxing factor whose effects are mediated by cAMP/cAMP-dependent protein kinase and cGMP/cGMP-dependent protein kinase, respectively. The results suggest that VASP phosphorylation is an important component of the inhibitory effects of prostacyclin and endothelium-derived relaxing factor on platelet activation and that VASP phosphorylation is a useful biochemical marker for the interaction of endothelial cells and platelets.