The Ras-JNK pathway is involved in shear-induced gene expression.
Hemodynamic forces play a key role in inducing atherosclerosis-implicated gene expression in vascular endothelial cells. To elucidate the signal transduction pathway leading to such gene expression, we studied the effects of fluid shearing on the activities of upstream signaling molecules. Fluid shearing (shear stress, 12 dynes/cm2 [1 dyne = 10(-5)N]) induced a transient and rapid activation of p21ras and preferentially activated c-Jun NH2 terminal kinases (JNK1 and JNK2) over extracellular signal-regulated kinases (ERK-1 and ERK-2). Cotransfection of RasN17, a dominant negative mutant of Ha-Ras, attenuated the shear-activated JNK and luciferase reporters driven by 12-O-tetradecanoylphorbol-13-acetate-responsive elements. JNK(K-R) and MEKK(K-M), the respective catalytically inactive mutants of JNK1 and MEKK, also partially inhibited the shear-induced luciferase reporters. In contrast, Raf301, ERK(K71R), and ERK(K52R), the dominant negative mutants of Raf-1, ERK-1, and ERK-2, respectively, had little effect on the activities of these reporters. The activation of JNK was also correlated with increased c-Jun transcriptional activity, which was attenuated by a negative mutant of Son of sevenless. Thus, mechanical stimulation exerted by fluid shearing activates primarily the Ras-MEKK-JNK pathway in inducing endothelial gene expression.
Department of Bioengineering, Institute for Biomedical Engineering, University of California, San Diego, La Jolla 92093, USA.
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D000818:Animals; D001011:Aorta; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000502:physiology*; D015870:Gene Expression; D017930:Genes, Reporter; D048031:JNK Mitogen-Activated Protein Kinases; D008156:Luciferases / Q000096:biosynthesis; D008565:Membrane Proteins / Q000096:biosynthesis; D048056:Mitogen-Activated Protein Kinase 9; D020928:Mitogen-Activated Protein Kinases; D008954:Models, Biological; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D015398:Signal Transduction; D020664:Son of Sevenless Proteins; D013314:Stress, Mechanical; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014162:Transfection
D008565:Membrane Proteins; D011994:Recombinant Proteins; D020664:Son of Sevenless Proteins; D018808:Transcription Factor AP-1; D008156:Luciferases; D011494:Protein Kinases; D048056:Mitogen-Activated Protein Kinase 9; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D016283:Proto-Oncogene Proteins p21(ras)