Angiotensin II stimulates phosphorylation of 4E-binding protein 1 and p70 S6 kinase in cultured vascular smooth muscle cells.
OBJECTIVE
To examine the regulatory effects of angiotensin II (Ang II) on the phosphorylation of 4E-binding protein 1 (4E-BP1) and p70 S6 kinase in cultured vascular smooth muscle cells (VSMC), and the contribution of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) signaling pathway in this process.


METHODS
VSMC obtained from rat thoracic aortas were cultured. The phosphorylation of 4E-BP1 and p70 S6 kinase was detected by immunoblotting.


RESULTS
Ang II significantly increased the phosphorylation of 4E-BP1 and p70 S6 kinase, with the peaks occurring at, respectively, 10 min and 30 min, after stimulation with Ang II. The stimulatory effect of Ang II on 4E-BP1 and p70 S6 kinase phosphorylation was abrogated by Ang II type 1 receptor (A(T1) receptor) antagonist losartan, and suppressed by PI3K inhibitor LY294002 in a concentration-dependent manner.


CONCLUSIONS
Ang II treatment of VSMC induces the phosphorylation of 4E-BP1 and p70 S6 kinase via A(T1) receptor, and PI3K signaling pathway is involved in this process.
Li
Na
N
Hypertension Institute, First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, China. lina2086@263.sina.com
Wu
Ke-gui
KG
Wang
Xiang-yu
XY
Xie
Liang-di
LD
Xu
Chang-sheng
CS
Wang
Hua-jun
HJ
D000804:Angiotensin II / Q000494:pharmacology*; D047228:Angiotensin II Type 1 Receptor Blockers; D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D002352:Carrier Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D002867:Chromones / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D019808:Losartan / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism*; D015398:Signal Transduction
D047228:Angiotensin II Type 1 Receptor Blockers; D002352:Carrier Proteins; D002867:Chromones; C499526:Eif4ebp1 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D009025:Morpholines; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins; D000804:Angiotensin II; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D019808:Losartan