Sphingosine 1-Phosphate Induces Platelet/Endothelial Cell Adhesion Molecule-1 Phosphorylation in Human Endothelial Cells through Csrc and Fyn

Sphingosine 1-phosphate (S1P) is a multifunctional phospholipid which acts through a specific family of G protein-coupled receptors. Platelet/ endothelial cell adhesion molecule-1 (PECAM-1) form trans-homophilic binding at lateral cell border. Upon stimulation, its cytoplasmic tyrosine residues could be phosphorylated and interact with various downstream signaling molecules. In this study, we demonstrated that S1P induced PECAM -1 tyrosine phosphorylation in human umbilical cord vein cells (HUVECs). By pharmacological inhibitors, it was suggested that G(i) and Src family kinases Were involved in PECAM-1 phosphorylation. Moreover, cSrc and Fyn siRNA significantly suppressed SI P-induced PECAM-1 phosphorylation. These results suggested that SI P-induced PECAM-1 phosphorylation through Gi and subsequent cSrc and Fyn. Our findings provide further understanding of SIP and PECAM-1 signaling as well as their functions in endothelial cells . (c) 2008 Elsevier Inc. All rights reserved