Activation of Akt/protein kinase B after stimulation with angiotensin II in vascular smooth muscle cells.
Involvement of Akt/Protein kinase B (PKB), a serine/threonine kinase with a pleckstrin-homology domain, in angiotensin II (ANG II)-induced signal transduction was investigated in cultured vascular smooth muscle cells (VSMC). Stimulation of the cells with ANG II led to a marked increase in the kinase activity of Akt/PKB, which coincided with Ser-473 phosphorylation. ANG II-stimulated Akt/PKB activation was rapid, concentration dependent, and inhibited by the AT1-receptor antagonist CV-11974, but not by pertussis toxin. Akt/PKB activity was stimulated by the Ca2+ ionophore ionomycin, suggesting the possible involvement of Ca2+ in ANG II-stimulated Akt/PKB activation. However, blockade of Ca2+ mobilization by BAPTA-AM only partially inhibited ANG II-stimulated Akt/PKB activation. ANG II-stimulated Akt/PKB activation was inhibited by the tyrosine kinase inhibitors genistein and herbimycin A and by the phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY-294002. These results indicate that ANG II stimulates Akt/PKB activity via AT1 receptors in VSMC and that the activities of tyrosine kinase and PI3K are required for this activation.
Takahashi
T
T
Department of Internal Medicine, First Division, Kobe University School of Medicine, Kobe 650, Japan.
Taniguchi
T
T
Konishi
H
H
Kikkawa
U
U
Ishikawa
Y
Y
Yokoyama
M
M
D000804:Angiotensin II / Q000494:pharmacology*; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D037342:Pertussis Toxin; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D057911:Angiotensin Receptor Antagonists; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D007476:Ionophores; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010982:Platelet-Derived Growth Factor; D011518:Proto-Oncogene Proteins; D010566:Virulence Factors, Bordetella; D000804:Angiotensin II; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D015759:Ionomycin; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D013755:Tetradecanoylphorbol Acetate