title: A role for PYK2 in ANG II-dependent regulation of the PHAS-1-eIF4E complex by multiple signaling cascades in vascular smooth muscle.
abstract: Regulation of the PHAS-1-eukaryotic initiation factor-4E (eIF4E) complex is the rate-limiting step in the initiation of protein synthesis. This study characterized the upstream signaling pathways that mediate ANG II-dependent phosphorylation of PHAS-1 and eIF4E in vascular smooth muscle. ANG II-dependent PHAS-1 phosphorylation was maximal at 10 min (2.47 +/- 0.3 fold vs. control). This effect was completely blocked by the specific inhibitors of phosphatidylinositol 3-kinase (PI3-kinase, LY-294002), mammalian target of rapamycin, and extracellular signal-regulated kinase 1/2 (ERK1/2, U-0126) or by a recombinant adenovirus encoding dominant-negative Akt. PHAS-1 phosphorylation was followed by dissociation of eIF4E. Increased ANG II-induced eIF4E phosphorylation was observed at 45 min (2.63 +/- 0.5 fold vs. control), was maximal at 90 min (3.38 +/- 0.3 fold vs. control), and was sustained at 2 h. This effect was blocked by inhibitors of the ERK1/2 and p38 mitogen-activated protein (MAP) kinase pathways, but not by PI3-kinase inhibition, and was dependent on PKC, intracellular Ca2+, and tyrosine kinases. Downregulation of proline-rich tyrosine kinase 2 (PYK2) by antisense oligonucleotides led to a near-complete inhibition of PHAS-1 and eIF4E phosphorylation in response to ANG II. Therefore, PYK2 represents a proximal signaling intermediate that regulates ANG II-induced vascular smooth muscle cell protein synthesis via regulation of the PHAS-1-eIF4E complex.
authors.affiliation: UAB Dept. of Physiology and Biophysics, MCLM-986, 1530 3rd Ave. S, Birmingham, AL 35294-0005, USA.
authors.forename: Petra
authors.initials: P
authors.lastname: Rocic
authors.forename: Hanjoong
authors.initials: H
authors.lastname: Jo
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Lucchesi
mesh_terms: D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D039561:Eukaryotic Initiation Factor-4E / Q000187:drug effects / Q000502:physiology*; D051418:Focal Adhesion Kinase 2; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010750:Phosphoproteins / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation; D011233:Precipitin Tests; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D013997:Time Factors
chemical_list: D000804:Angiotensin II; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D039561:Eukaryotic Initiation Factor-4E; D051418:Focal Adhesion Kinase 2; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; C499526:Eif4ebp1 protein, rat; C496054:Ptk2b protein, rat; C494920:Akt1 protein, rat