title: Direct phosphorylation and regulation of poly(ADP-ribose) polymerase-1 by extracellular signal-regulated kinases 1/2.
abstract: Sustained activation of poly(ADP-ribose) polymerase-1 (PARP-1) and extracellular signal-regulated kinases 1/2 (ERK1/2) both promote neuronal death. Here we identify a direct link between these two cell death pathways. In a rat model of hypoglycemic brain injury, neuronal PARP-1 activation and subsequent neuronal death were blocked by the ERK1/2 inhibitor 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one (PD98059). In neuron cultures, PARP-1-mediated neuronal death induced by N-methyl-d-aspartate, peroxynitrite, or DNA alkylation was similarly blocked by ERK1/2 pathway inhibitors. These inhibitors also blocked PARP-1 activation and PARP-1-mediated death in astrocytes. siRNA down-regulation of ERK2 expression in astrocytes also blocked PARP-1 activation and cell death. Direct effects of ERK1/2 on PARP-1 were evaluated by using isolated recombinant enzymes. The activity of recombinant human PARP-1 was reduced by incubation with alkaline phosphatase and restored by incubation with active ERK1 or ERK2. Putative ERK1/2 phosphorylation sites on PARP-1 were identified by mass spectrometry. Using site-directed mutagenesis, these sites were replaced with alanine (S372A and T373A) to block phosphorylation, or with glutamate (S372E and T373E) to mimic constitutive phosphorylation. Transfection of PARP-1 deficient mouse embryonic fibroblasts with the mutant PARP-1 species showed that the S372A and T373A mutations impaired PARP-1 activation, whereas the S372E and T373E mutations increased PARP-1 activity and eliminated the effect of ERK1/2 inhibitors on PARP-1 activation. These results suggest that PARP1 phosphorylation by ERK1/2 is required for maximal PARP-1 activation after DNA damage.
authors.affiliation: Department of Neurology, University of California, San Francisco, and Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.
authors.forename: Tiina M
authors.initials: TM
authors.lastname: Kauppinen
authors.forename: Wai Y
authors.initials: WY
authors.lastname: Chan
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Suh
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Wiggins
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Huang
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Swanson
mesh_terms: D000818:Animals; D016923:Cell Death; D002478:Cells, Cultured; D004789:Enzyme Activation; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D007003:Hypoglycemia / Q000378:metabolism / Q000473:pathology; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D010766:Phosphorylation; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2