title: Mitogen-activated protein kinase (ERK1/2) activation by shear stress and adhesion in endothelial cells. Essential role for a herbimycin-sensitive kinase.
abstract: Fluid shear stress modulates vascular function and structure by stimulating mechanosensitive endothelial cell signal events. Cell adhesion, mediated by integrin-matrix interactions, also regulates intracellular signaling by mechanosensitive events. To gain insight into the role of integrin-matrix interactions, we compared tyrosine phosphorylation and extracellular signal-regulated kinase (ERK1/2) activation in adhesion- and shear stress-stimulated human umbilical vein endothelial cells (HUVEC). Adhesion of HUVEC to fibronectin, but not to poly-L-lysine, rapidly activated ERK1/2. Fluid shear stress (12 dyn/cm2) enhanced ERK1/2 activation stimulated by adhesion, suggesting the presence of a separate pathway. Two differences in signal transduction were identified: focal adhesion kinase phosphorylation was increased rapidly by adhesion but not by shear stress; and ERK1/2 activation in response to adhesion was inhibited to a significantly greater extent when actin filaments were disrupted by cytochalasin D. Two similarities in activation of ERK1/2 were observed: protein kinase C (PKC) activity was necessary as shown by complete inhibition when PKC was downregulated; and an herbimycin-sensitive (genistein- and tyrphostin-insensitive) tyrosine kinase was required. c-Src was identified as a candidate tyrosine kinase as it was activated by both shear stress and adhesion. These findings suggest that adhesion and shear stress activate ERK1/2 via a shared pathway that involves an herbimycin-sensitive tyrosine kinase and PKC. In addition, shear stress activates ERK1/2 through another pathway that is partially independent of cytoskeletal integrity.
authors.affiliation: Department of Medicine, University of Washington, Seattle 98195-7710, USA.
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: B C
authors.initials: BC
authors.lastname: Berk
mesh_terms: D000936:Antigen-Antibody Complex / Q000032:analysis; D016227:Benzoquinones; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002448:Cell Adhesion; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006801:Humans; D047029:Lactams, Macrocyclic; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology*; D017828:Rifabutin / Q000031:analogs & derivatives; D013314:Stress, Mechanical; D014471:Umbilical Veins; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000936:Antigen-Antibody Complex; D016227:Benzoquinones; D004791:Enzyme Inhibitors; D047029:Lactams, Macrocyclic; D011809:Quinones; D017828:Rifabutin; C020754:herbimycin; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src); D019061:src-Family Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases