system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, RESULTS. Meshes: Angiopoietin-1, Angiopoietin-2, Angiopoietins, Cell Hypoxia, Cell Movement, Cell Survival, Cells, Cultured, Endothelial Cells, Gene Expression Regulation, Enzymologic, Humans, Phosphorylation, RNA, Messenger, RNA, Small Interfering, Receptor, TIE-2, Receptor-Like Protein Tyrosine Phosphatases, Class 5, Signal Transduction, Vanadates.
user
Does tyrosine phosphatase beta regulate angiopoietin-Tie2 signaling in human endothelial cells? Context: The endothelial cell (EC)-selective receptor tyrosine kinase, Tie2, and its ligands angiopoietin Ang-1 and Ang-2, are essential for blood vessel maintenance and repair. Ang-1 is an agonist of Tie2 receptor activation, whereas Ang-2 is a context-dependent antagonist/agonist. Therefore, we investigated the role of the EC-selective phosphatase, human protein tyrosine phosphatase beta (HPTPbeta), in regulating Tie2 activity. siRNA silencing of HPTPbeta enhanced Ang-1 and Ang-2-induced Tie2 phosphorylation at 10 min (2.5-fold, P < 0.001; and 1.8-fold, P < 0.05, respectively). The cell survival response to Ang-1, but not Ang-2, was enhanced by HPTPbeta silencing as measured by flow cytometry (0.85-fold to 0.66-fold, P < 0.05) and ELISA (0.88-fold to 0.53-fold, P < 0.01). Hypoxia, which upregulated HPTPbeta expression in endothelial cells, impaired Ang-1-induced Tie2 phosphorylation.
assistant
These results reveal a novel role for HPTPbeta in modulating Ang-1-Tie2 signaling and endothelial cell survival. Final Decision: yes