1. PECAM1 regulates flow-mediated Gab1 tyrosine phosphorylation and signaling
- Author
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Zheng Gen Jin, Chang Hoon Ha, Michael A. Mastrangelo, Marina Koroleva, Meimei Yin, Felix Q Jin, Keigi Fujiwara, Weiye Wang, Xiangbin Xu, and Suowen Xu
- Subjects
0301 basic medicine ,Nitric Oxide Synthase Type III ,Morpholines ,Protein Tyrosine Phosphatase, Non-Receptor Type 11 ,030204 cardiovascular system & hematology ,Article ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Enos ,medicine ,Human Umbilical Vein Endothelial Cells ,Animals ,Humans ,Tyrosine ,Phosphorylation ,RNA, Small Interfering ,Protein kinase B ,PI3K/AKT/mTOR pathway ,Adaptor Proteins, Signal Transducing ,Mice, Knockout ,biology ,Hepatocyte Growth Factor ,Tyrosine phosphorylation ,Cell Biology ,biology.organism_classification ,Phosphoproteins ,Recombinant Proteins ,Cell biology ,Mice, Inbred C57BL ,Platelet Endothelial Cell Adhesion Molecule-1 ,030104 developmental biology ,Biochemistry ,chemistry ,Chromones ,Hepatocyte growth factor ,RNA Interference ,Signal transduction ,Proto-Oncogene Proteins c-akt ,medicine.drug ,Signal Transduction - Abstract
Endothelial dysfunction, characterized by impaired activation of endothelial nitric oxide (NO) synthase (eNOS) and ensued decrease of NO production, is a common mechanism of various cardiovascular pathologies, including hypertension and atherosclerosis. Laminar blood flow-mediated specific signaling cascades modulate vascular endothelial cells (ECs) structure and functions. We have previously shown that flow-stimulated Gab1 (Grb2-associated binder-1) tyrosine phosphorylation mediates eNOS activation in ECs, which in part confers laminar flow atheroprotective action. However, the molecular mechanisms whereby flow regulates Gab1 tyrosine phosphorylation and its downstream signaling events remain unclear. Here we show that platelet endothelial cell adhesion molecule-1 (PECAM1), a key molecule in an endothelial mechanosensing complex, specifically mediates Gab1 tyrosine phosphorylation and its downstream Akt and eNOS activation in ECs upon flow rather than hepatocyte growth factor (HGF) stimulation. Small interfering RNA (siRNA) targeting PECAM1 abolished flow- but not HGF-induced Gab1 tyrosine phosphorylation and Akt, eNOS activation as well as Gab1 membrane translocation. Protein-tyrosine phosphatase SHP2, which has been shown to interact with Gab1, was involved in flow signaling and HGF signaling, as SHP2 siRNA diminished the flow- and HGF-induced Gab1 tyrosine phosphorylation, membrane localization and downstream signaling. Pharmacological inhibition of PI3K decreased flow-, but not HGF-mediated Gab1 phosphorylation and membrane localization as well as eNOS activation. Finally, we observed that flow-mediated Gab1 and eNOS phosphorylation in vivo induced by voluntary wheel running was reduced in PECAM1 knockout mice. These results demonstrate a specific role of PECAM1 in flow-mediated Gab1 tyrosine phosphorylation and eNOS signaling in ECs.
- Published
- 2015