Role of Cbl in shear-activation of PI 3-kinase and JNK in endothelial cells.
Fluid shear stress can activate PI-3 kinase and JNK in vascular endothelial cells. This study was designed to establish the role of Cbl as an upstream molecule in the shear stress activation of PI-3 kinase and JNK. Confluent monolayers of bovine aortic endothelial cells (BAECs) were subjected to a shear stress of 12 dyn/cm(2) over intervals ranging from 0.5 to 30 min. Shear stress increased Cbl phosphorylation to 2.9-fold of control and Cbl association with the regulatory PI-3 kinase subunit p85 to 5.4-fold. The PI-3 kinase activity measured in Cbl-immunoprecipitated complexes increased to 11.7-fold in response to shear, suggesting that the shear stress activation of PI-3 kinase involves its association with Cbl. Furthermore, the shear stress induction of JNK was attenuated by a negative mutant of Cbl. Finally, shear stress caused an activation of PI 3-kinase only in BAECs seeded onto fibronectin, vitronectin, or laminin, but not poly-l-lysine. Our results suggest that Cbl plays a critical role in the shear stress induction of PI 3-kinase and JNK activities, and that this shear-induced activation requires the interaction of endothelial integrins with extracellular matrix proteins.
Miao
Hui
H
Department of Bioengineering, University of California at San Diego, La Jolla, California 92093-0427, USA.
Yuan
Suli
S
Wang
Yingxiao
Y
Tsygankov
Alexander
A
Chien
Shu
S
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D004790:Enzyme Induction / Q000502:physiology; D005109:Extracellular Matrix / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D021381:Protein Transport / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D050721:Proto-Oncogene Proteins c-cbl; D015398:Signal Transduction / Q000502:physiology; D013314:Stress, Mechanical; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
D016023:Integrins; D011518:Proto-Oncogene Proteins; D014443:Tyrosine; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D019869:Phosphatidylinositol 3-Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases