title: Rho-mediated phosphorylation of focal adhesion kinase and myosin light chain in human endothelial cells stimulated with sphingosine 1-phosphate, a bioactive lysophospholipid released from activated platelets.
abstract: Since sphingosine 1-phosphate (Sph-1-P) is stored in abundant amounts in blood platelets and released extracellularly upon stimulation, it is important to clarify the effects of this bioactive lysophospholipid on vascular endothelial cells from the viewpoint of platelet-endothelial cell interactions. In this study, we investigated the effects of Sph-1-P on the cytoskeletal remodeling of human umbilical vein endothelial cells (HUVECs). Of a focal adhesion kinase (FAK) family of non-receptor protein-tyrosine kinases, HUVECs were found to express FAK, but scarcely proline-rich tyrosine kinase 2. Sph-1-P induced FAK tyrosine phosphorylation, myosin light chain phosphorylation, and the formation of stress fibers in HUVECs. The specific Rho inactivator C3 transferase from Clostridium botulinum abolished all of these cytoskeletal responses induced by Sph-1-P, while pertussis toxin only partly inhibited FAK tyrosine phosphorylation, and hardly affected myosin light chain phosphorylation and stress fiber formation. In contrast, Sph-1-P-induced intracellular Ca(2)(+) mobilization was suppressed by pertussis toxin, but not at all by C3 exoenzyme. Our results suggest that Sph-1-P, a bioactive lipid released from activated platelets, induces endothelial cell cytoskeletal reorganization, mainly through Rho-mediated signaling pathways.
authors.affiliation: Department of Laboratory Medicine, Yamanashi Medical University, Nakakoma, Yamanashi 409-3898, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Miura
authors.forename: Y
authors.initials: Y
authors.lastname: Yatomi
authors.forename: G
authors.initials: G
authors.lastname: Rile
authors.forename: T
authors.initials: T
authors.lastname: Ohmori
authors.forename: K
authors.initials: K
authors.lastname: Satoh
authors.forename: Y
authors.initials: Y
authors.lastname: Ozaki
mesh_terms: D003599:Cytoskeleton / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000187:drug effects*; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D006801:Humans; D008246:Lysophospholipids / Q000378:metabolism*; D018994:Myosin Light Chains / Q000378:metabolism; D010766:Phosphorylation; D015539:Platelet Activation / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
chemical_list: D008246:Lysophospholipids; D018994:Myosin Light Chains; C060506:sphingosine 1-phosphate; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D020741:rho GTP-Binding Proteins; D013110:Sphingosine