A role for PYK2 in ANG II-dependent regulation of the PHAS-1-eIF4E complex by multiple signaling cascades in vascular smooth muscle

Am J Physiol Cell Physiol. 2003 Dec;285(6):C1437-44. doi: 10.1152/ajpcell.00075.2003. Epub 2003 Jul 30.

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Angiotensin II / metabolism
  • Animals
  • Carrier Proteins / drug effects
  • Carrier Proteins / physiology*
  • Cells, Cultured
  • Enzyme Inhibitors / pharmacology
  • Eukaryotic Initiation Factor-4E / drug effects
  • Eukaryotic Initiation Factor-4E / physiology*
  • Focal Adhesion Kinase 2
  • Immunoblotting
  • Intracellular Signaling Peptides and Proteins
  • MAP Kinase Signaling System / physiology*
  • Male
  • Mitogen-Activated Protein Kinases / physiology
  • Muscle, Smooth, Vascular / enzymology*
  • Mutation
  • Phosphatidylinositol 3-Kinases / physiology
  • Phosphoproteins / drug effects
  • Phosphoproteins / physiology*
  • Phosphorylation
  • Precipitin Tests
  • Protein Biosynthesis
  • Protein-Serine-Threonine Kinases*
  • Protein-Tyrosine Kinases / physiology*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-akt
  • Rats
  • Time Factors

Substances

  • Carrier Proteins
  • Eif4ebp1 protein, rat
  • Enzyme Inhibitors
  • Eukaryotic Initiation Factor-4E
  • Intracellular Signaling Peptides and Proteins
  • Phosphoproteins
  • Proto-Oncogene Proteins
  • Angiotensin II
  • Protein-Tyrosine Kinases
  • Focal Adhesion Kinase 2
  • Ptk2b protein, rat
  • Akt1 protein, rat
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Mitogen-Activated Protein Kinases