title: Sphingosine-1-phosphate inhibition of apoptosis requires mitogen-activated protein kinase phosphatase-1 in mouse fibroblast C3H10T 1/2 cells.
abstract: The roles of extracellular regulated kinase (ERK) activation and mitogen-activated protein kinase phosphatase-1 (MKP-1) were examined in sphingosine-1-phosphate (S1P)-mediated inhibition of apoptosis in C3H10T 1/2 fibroblast cells. Apoptosis induced by the ceramide analog, C8-ceramine, was inhibited by S1P (ceramine/S1P). Stress activated protein kinase or c-Jun N-terminal kinase (SAPK/JNK) activation was significantly higher after ceramine and ceramine/S1P treatments. Ceramine/S1P treatment also significantly increased ERK activation and MKP-1 protein levels. ERK activation was required for the inhibition of apoptosis by S1P as shown using the mitogen-activated protein kinase kinase inhibitor, PD98059. Transfection with a dominant negative mutant construct of the MKP-1 gene prevented S1P inhibition of apoptosis and resulted in sustained SAPK/JNK activity. The MKP-1 mutant did not affect ERK activity, indicating that MKP-1 preferentially down-regulates SAPK/JNK in C3H10T 1/2 cells. Finally, the S1P activation of ERK and inhibition of apoptosis were reduced by pertussis toxin treatment, suggesting that G-protein-coupled receptors, such as the endothelial differentiation gene (EDG) receptor, play a role. Thus, both ERK activation and MKP-1, which down-regulates SAPK/JNK, are required for S1P-mediated inhibition of apoptosis.
authors: Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907-1264, USA.
authors: S Sianna
authors: SS
authors: Castillo
authors: Dorothy
authors: D
authors: Teegarden
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D054638:Dual Specificity Phosphatase 1; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D005419:Flavonoids / Q000494:pharmacology; D017874:Immediate-Early Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008246:Lysophospholipids / Q000494:pharmacology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology*; D014162:Transfection
chemical_list: D018797:Cell Cycle Proteins; D004791:Enzyme Inhibitors; D005419:Flavonoids; D017874:Immediate-Early Proteins; D008246:Lysophospholipids; D011994:Recombinant Proteins; C060506:sphingosine 1-phosphate; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse; D017027:Protein Tyrosine Phosphatases; D013110:Sphingosine; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one