Stress-activated protein kinases (JNK and p38/HOG) are essential for vascular endothelial growth factor mRNA stability.
Stability of the vascular endothelial growth factor (VEGF) mRNA is tightly regulated through its 3'-untranslated region (3'-UTR). Here, we demonstrate that VEGF mRNA levels are increased by anisomycin, a strong activator of stress-activated protein kinases. Hence, VEGF mRNA induction is inhibited by SB202190, an inhibitor of JNK and p38/HOG kinase. Furthermore, VEGF mRNA expression is increased in cells that overexpress JNK and p38/HOG by an increase in its stability. We show by two different approaches that anisomycin exerts its effect on the VEGF mRNA 3'-UTR. First, by using an in vitro mRNA degradation assay, the half-life of the VEGF mRNA 3'-UTR region transcript was found to be increased when incubated with extracts from anisomycin-treated cells; and second, the 3'-UTR was also sufficient to confer mRNA instability to the Nhe3 (Na(+)/H(+) exchanger 3) heterologous reporter gene, and anisomycin treatment stabilized the chimeric mRNA (Nhe3 fused to the VEGF mRNA 3'-UTR). This chimeric mRNA is also more stable in cells overexpressing p38/HOG and JNK that have been stimulated by anisomycin. We show that such regulation is mediated through an AU-rich region of the 3'-UTR contained within a stable hairpin structure. By RNA electrophoretic mobility shift assays, we show that this region binds proteins specifically induced by anisomycin treatment. These findings clearly demonstrate a major role of stress-activated protein kinases in the post-transcriptional regulation of VEGF.
Pagès
G
G
Institute of Signaling, Developmental Biology, and Cancer Research, CNRS UMR 6543, 33 Avenue de Valombrose, 06189 Nice, France. gpages@unice.fr
Berra
E
E
Milanini
J
J
Levy
A P
AP
Pouysségur
J
J
D000841:Anisomycin / Q000494:pharmacology; D016228:Endothelial Growth Factors / Q000235:genetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D008222:Lymphokines / Q000235:genetics*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D048051:p38 Mitogen-Activated Protein Kinases
D016228:Endothelial Growth Factors; D004791:Enzyme Inhibitors; D007093:Imidazoles; D008222:Lymphokines; D011500:Protein Synthesis Inhibitors; D011725:Pyridines; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D000841:Anisomycin; C088589:HOG1 protein, S cerevisiae; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole