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Flow activates ERK1/2 and endothelial nitric oxide synthase via a pathway involving PECAM1, SHP2, and Tie2
- Source :
- The Journal of biological chemistry. 280(33)
- Publication Year :
- 2005
-
Abstract
- Blood flow modulates endothelial cell (EC) functions through specific signaling events. Previous data show that flow stimulates SHP2 translocation to cell membranes and binding to phosphotyrosine proteins. Flow-induced ERK1/2 phosphorylation depends on SHP2 phosphatase activity and SHP2 binding to phospho-PECAM1 (platelet endothelial adhesion molecule 1), suggesting that SHP2 forms a signaling module with PECAM1. We hypothesized that flow induces assembly of the multi-protein complexes with SHP2 that are required for downstream signaling. ECs were exposed to flow for 10 min, and endogenous SHP2 was immunoprecipitated. SHP2-associated proteins were analyzed by SDS-PAGE and identified by mass spectrometry. Tie2 and several known SHP2-binding proteins were identified in flow-induced SHP2 complexes. Flow significantly increased tyrosine phosphorylation of both Tie2 and PECAM1 and their association with SHP2. To evaluate their functional roles, ECs were treated with Tie2 or PECAM1 small interfering RNA (siRNA). Tie2 and PECAM1 expression decreased >80% after siRNA treatment, and flow-stimulated phosphorylation of ERK1/2, Akt, and endothelial nitric oxide synthase was significantly inhibited by Tie2 and PECAM1 siRNA. Tie2 phosphorylation by flow was significantly inhibited by PECAM1 siRNA treatment. These results establish Tie2 transactivation via PECAM1 as an early event in flow-mediated mechanotransduction and suggest an important role for a PECAM1-SHP2-Tie2 pathway in flow-mediated signal transduction.
- Subjects :
- Transcriptional Activation
Small interfering RNA
Nitric Oxide Synthase Type III
Proto-Oncogene Proteins c-akt
Protein Tyrosine Phosphatase, Non-Receptor Type 11
Protein tyrosine phosphatase
Biology
Protein Serine-Threonine Kinases
Biochemistry
Transactivation
Proto-Oncogene Proteins
Animals
Humans
Phosphorylation
Molecular Biology
Protein kinase B
Cells, Cultured
Mitogen-Activated Protein Kinase 1
Mitogen-Activated Protein Kinase 3
Intracellular Signaling Peptides and Proteins
Cell Biology
Molecular biology
Receptor, TIE-2
Cell biology
Enzyme Activation
Platelet Endothelial Cell Adhesion Molecule-1
Blood Circulation
Cattle
Signal transduction
Nitric Oxide Synthase
Protein Tyrosine Phosphatases
Signal Transduction
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 280
- Issue :
- 33
- Database :
- OpenAIRE
- Journal :
- The Journal of biological chemistry
- Accession number :
- edsair.doi.dedup.....86bc0cb328c4c2c2ccb6328740d3c758