JNK1 physically interacts with WW domain-containing oxidoreductase (WOX1) and inhibits WOX1-mediated apoptosis.
Transient activation of c-Jun N-terminal kinase (JNK) promotes cell survival, whereas persistent JNK activation induces apoptosis. Bovine testicular hyaluronidase PH-20 activates JNK1 and protects L929 fibroblasts from staurosporine-mediated cell death. PH-20 also induces the expression of a p53-interacting WW domain-containing oxidoreductase (WOX1, also known as WWOX or FOR) in these cells. WOX1 enhances the cytotoxic function of tumor necrosis factor and mediates apoptosis synergistically with p53. Thus, the activated JNK1 is likely to counteract WOX1 in mediating apoptosis. Here it is demonstrated that ectopic JNK1 inhibited WOX1-mediated apoptosis of L929 fibroblasts, monocytic U937 cells, and other cell types. Also, JNK1 blocked WOX1 prevention of cell cycle progression. By stimulating cells with anisomycin or UV light, JNK1 became activated, and WOX1 was phosphorylated at Tyr(33). The activated JNK1 physically interacted with the phosphorylated WOX1, as determined by co-immunoprecipitation. Alteration of Tyr(33) to Arg(33) in WOX1 abrogated its binding interaction with JNK1 and its activity in mediating cell death, indicating that Tyr(33) phosphorylation is needed to activate WOX1. A dominant negative WOX1 was developed and shown to block p53-mediated apoptosis and anisomycin-mediated WOX1 phosphorylation but could not inhibit JNK1 activation. This mutant protein bound p53 but could not interact with JNK1, as determined in yeast two-hybrid analysis. Taken together, phosphorylation of JNK1 and WOX1 is necessary for their physical interaction and functional antagonism.
Chang
Nan-Shan
NS
Guthrie Research Institute, Laboratory of Molecular Immunology, Guthrie Medical Center, Sayre, Pennsylvania 18840, USA. nschang@inet.guthrie.org
Doherty
Joan
J
Ensign
Amy
A
D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D017209:Apoptosis; D001120:Arginine / Q000737:chemistry; D002453:Cell Cycle; D002470:Cell Survival; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D005347:Fibroblasts / Q000378:metabolism; D005799:Genes, Dominant; D006801:Humans; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology; D051379:Mice; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D013997:Time Factors; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques; D014443:Tyrosine / Q000737:chemistry; D020298:U937 Cells; D014466:Ultraviolet Rays; D000074584:WW Domain-Containing Oxidoreductase
D018076:DNA, Complementary; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D014443:Tyrosine; D000841:Anisomycin; D001120:Arginine; D010088:Oxidoreductases; D000074584:WW Domain-Containing Oxidoreductase; C486071:WWOX protein, human; C428130:Wwox protein, mouse; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases; D006821:Hyaluronoglucosaminidase