title: Role of SHP-1, Kv.1.2, and cGMP in nitric oxide-induced ERK1/2 MAP kinase dephosphorylation in rat vascular smooth muscle cells.
abstract: OBJECTIVE
  Nitric oxide (NO) elicits relaxation in vascular smooth muscle cells (VSMC) that is associated with guanylate cyclase (GC) and K(+) channel activation. In this study we determined the mechanisms that lead to ERK1/2 MAP kinase dephosphorylation in response to NO.
  
  
  METHODS
  VSMC were treated with the NO donor SNAP or sodium nitroprusside (SNP), and ERK1/2, Src homology (SH) 1 domain-containing protein tyrosine phosphatase (SHP-1), and Kv.1.2 phosphorylation were assessed by immunoprecipitation and Western blot analysis.
  
  
  RESULTS
  NO decreased basal ERK1/2 phosphorylation in a dose- and time-dependent manner. NO-induced ERK1/2 dephosphorylation was detected at 1 min and sustained for 30 min. Pre-treatment with the GC inhibitor ODQ or the protein tyrosine phosphatase inhibitor I prevented ERK1/2 dephosphorylation induced by SNAP. The inhibition of protein phosphatase 1A/2A had no effect on ERK1/2 dephosphorylation induced by SNAP. Treatment with cromakalim A, a nonspecific K(+) channel activator, also induced ERK1/2 dephosphorylation, while blockade of Kv.1.2 K(+) channels (AM92016 hydrochloride) prevented NO-induced ERK1/2 dephosphorylation. In addition, SNAP induced SHP-1 phosphorylation, and the Kv.1.2 dephosphorylation increase and SHP-1 phosphorylation was blocked by ODQ or AM92016. The basal interaction between ERK1/2 and SHP-1 was decreased in response to SNAP stimulation. SHP-1 also interacted with Kv.1.2 under basal conditions and participates in Kv.1.2 activation. Using the mouse mesenteric resistance artery, we found that ERK1/2 MAP kinase is involved in regulation of myogenic tone.
  
  
  CONCLUSIONS
  Thus, our study provides the first evidence that NO controls basal ERK1/2 phosphorylation by a signaling cascade that involves a dynamic signaling complex between cGMP, Kv.1.2 and SHP-1.
authors.affiliation: Department of Pharmacology, LSU Health Sciences Center at New Orleans, LA 70112, USA.
authors.forename: Desiree I
authors.initials: DI
authors.lastname: Palen
authors.forename: Souad
authors.initials: S
authors.lastname: Belmadani
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Lucchesi
authors.forename: Khalid
authors.initials: K
authors.lastname: Matrougui
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic; D015153:Blotting, Western / Q000379:methods; D002478:Cells, Cultured; D019806:Cromakalim / Q000494:pharmacology; D006152:Cyclic GMP / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051663:Kv1.2 Potassium Channel / Q000378:metabolism*; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D019319:Okadaic Acid / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D051663:Kv1.2 Potassium Channel; D020030:Nitric Oxide Donors; C110881:S-nitro-N-acetylpenicillamine; D014665:Vasodilator Agents; D019806:Cromakalim; D009599:Nitroprusside; D019319:Okadaic Acid; D009569:Nitric Oxide; D020929:Mitogen-Activated Protein Kinase Kinases; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C509248:Ptpn6 protein, mouse; C509250:Ptpn6 protein, rat; D010396:Penicillamine; D006152:Cyclic GMP