Double-stranded RNA-activated protein kinase interacts with apoptosis signal-regulating kinase 1. Implications for apoptosis signaling pathways.
Double-stranded RNA-activated protein kinase (PKR), a serine/threonine kinase, is activated in virus-infected cells and acts as an antiviral machinery of type I interferons. PKR controls several stress response pathways induced by double-stranded RNA, tumor necrosis factor-alpha or lipopolysaccharide, which result in the activation of stress-activated protein kinase/c-Jun NH2-terminal kinase and p38 of the mitogen-activated protein kinase family. Here we showed a novel interaction between PKR and apoptosis signal-regulating kinase 1 (ASK1), one of the members of the mitogen-activated protein kinase kinase kinase family, which is activated in response to a variety of apoptosis-inducing stimuli. PKR and ASK1 showed predominant cytoplasmic localization in COS-1 cells transfected with both cDNAs, and coimmunoprecipitated from the cell extracts. A dominant negative mutant of PKR (PKR-KR) inhibited both the apoptosis and p38 activation induced by ASK1 in vivo. Consistently, PKR-KR inhibited the autophosphorylation of ASK1 in vitro, and exposure to poly(I)-poly(C) increased the phosphorylation of ASK1 in vivo. These results indicate the existence of a link between PKR and ASK1, which modifies downstream MAPK.
Takizawa
Takenori
T
Department of Biochemistry, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Aichi, Japan. takizawa@inst-hsc.pref.aichi.jp
Tatematsu
Chizuru
C
Nakanishi
Yoshinobu
Y
D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D019556:COS Cells; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015151:Immunoblotting; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D015398:Signal Transduction; D014162:Transfection; D019892:eIF-2 Kinase / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases
D018076:DNA, Complementary; D004247:DNA; D019892:eIF-2 Kinase; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; D020930:MAP Kinase Kinase Kinases; C482858:MAP3K5 protein, human