title: A role for mitogen-activated protein kinase(Erk1/2) activation and non-selective pore formation in P2X7 receptor-mediated thymocyte death.
abstract: Extracellular ATP (ATPe) binds to P2X7 receptors (P2X7R) expressed on the surface of cells of hematopoietic lineage, including murine thymocytes. Activation of P2X7R by ATPe results in the opening of cation-specific channels, and prolonged ATPe exposure leads to the formation of non-selective pores enabling transmembrane passage of solutes up to 900 Da. In the presence of ATPe, P2X7R-mediated thymocyte death is due primarily to necrosis/lysis and not apoptosis, as measured by the release of lactate dehydrogenase indicative of a loss of plasma membrane integrity. The present study is focused on the identification of P2X7R signaling mediators in ATP-induced thymocyte necrosis/lysis. Thus, extracellular signal-regulated protein kinase 1/2 (Erk1/2) phosphorylation was found to be required for cell lysis, and both events were independent of ATP-induced calcium influx. P2X7R-dependent thymocyte death involved the chronological activation of Src family tyrosine kinase(s), phosphatidylinositol 3-kinase, the mitogen-activated protein (MAP) kinase(Erk1/2) module, and the proteasome. Although independent of this signaling cascade, non-selective pore formation may modulate ATP-mediated thymocyte death. These results therefore suggest a role for both activation of MAP kinase(Erk1/2) and non-selective pore opening in P2X7R-induced thymocyte death.
authors.affiliation: Institut de Biochimie et Biophysique Moléculaire et Cellulaire, Université Paris-Sud, 91405 Orsay cedex, France.
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Auger
authors.forename: Iris
authors.initials: I
authors.lastname: Motta
authors.forename: Karim
authors.initials: K
authors.lastname: Benihoud
authors.forename: David M
authors.initials: DM
authors.lastname: Ojcius
authors.forename: Jean M
authors.initials: JM
authors.lastname: Kanellopoulos
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D016923:Cell Death; D002462:Cell Membrane / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004996:Ethidium / Q000494:pharmacology; D047468:Immunoprecipitation; D007364:Intercalating Agents / Q000494:pharmacology; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D020935:MAP Kinase Signaling System; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009336:Necrosis; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D017434:Protein Structure, Tertiary; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013950:Thymus Gland / Q000166:cytology*; D013997:Time Factors
chemical_list: D004791:Enzyme Inhibitors; D007364:Intercalating Agents; C546469:P2rx7 protein, mouse; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases; D004996:Ethidium; D002118:Calcium