Abstract
Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are produced during cell activation and have multiple effects on cells. A family of seven transmembrane-spanning domain G-protein-coupled receptors, named Edg, mediate these effects of LPA and S1P. In this study, transient overexpression of Edg-2 sensitized MG63 human osteosarcoma cells to both LPA- and S1P-mediated stimulation of fibronectin matrix deposition and actin stress fiber formation. Both lipids were active in the 1-20 nM concentration range on cells transfected with Edg-2 as compared to the 10-200 nM range on mock-transfected cells. The signaling pathway for matrix deposition by Edg-2-transfected cells was Rho dependent. Overexpression of Edg-2 also caused a tenfold decrease in the concentration of either LPA or S1P that activated MAPKinase (Erkl/2) in MG63 cells. LPA- or S1P-stimulated activation of Erkl/2 was Gi dependent. These results indicate that, in MG63 cells, Edg-2 mediates actin stress fiber formation, fibronectin matrix assembly, and MAPKinase activation in response to either LPA or S1P.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Actins / metabolism
-
Dose-Response Relationship, Drug
-
Extracellular Matrix / metabolism
-
Fibronectins / metabolism
-
Fluorescein-5-isothiocyanate
-
Gene Expression Regulation, Neoplastic / drug effects
-
Green Fluorescent Proteins
-
Humans
-
Luminescent Proteins
-
Lysophospholipids / pharmacology*
-
MAP Kinase Signaling System / drug effects*
-
Microscopy, Fluorescence
-
Mitogen-Activated Protein Kinases / metabolism
-
Nuclear Proteins / genetics
-
Nuclear Proteins / metabolism*
-
Osteosarcoma / metabolism
-
Phosphorylation
-
RNA, Messenger / metabolism
-
Receptors, Cell Surface*
-
Receptors, G-Protein-Coupled*
-
Receptors, Lysophosphatidic Acid
-
Sphingosine / analogs & derivatives*
-
Sphingosine / pharmacology
-
Transcription Factors / genetics
-
Transcription Factors / metabolism*
-
Transfection
-
Tumor Cells, Cultured
-
rho GTP-Binding Proteins / metabolism
Substances
-
Actins
-
Fibronectins
-
Luminescent Proteins
-
Lysophospholipids
-
Nuclear Proteins
-
RNA, Messenger
-
Receptors, Cell Surface
-
Receptors, G-Protein-Coupled
-
Receptors, Lysophosphatidic Acid
-
Transcription Factors
-
Green Fluorescent Proteins
-
sphingosine 1-phosphate
-
Mitogen-Activated Protein Kinases
-
rho GTP-Binding Proteins
-
Fluorescein-5-isothiocyanate
-
Sphingosine