Angiotensin II induces RhoA activation through SHP2-dependent dephosphorylation of the RhoGAP p190A in vascular smooth muscle cells
| Autor: | Malvyne Rolli-Derkinderen, Jérémy Brégeon, Gervaise Loirand, Pierre Pacaud |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
medicine.medical_specialty
RHOA Vascular smooth muscle Physiology Blotting Western Myocytes Smooth Muscle Protein Tyrosine Phosphatase Non-Receptor Type 11 Muscle Smooth Vascular Receptor Angiotensin Type 1 Dephosphorylation Internal medicine Renin–angiotensin system medicine Animals Immunoprecipitation Myocyte Phosphorylation RNA Small Interfering Receptor rho-Associated Kinases biology Reverse Transcriptase Polymerase Chain Reaction Angiotensin II GTPase-Activating Proteins Cell Biology Rats Enzyme Activation Endocrinology cardiovascular system biology.protein rhoA GTP-Binding Protein Signal Transduction |
| Zdroj: | American Journal of Physiology-Cell Physiology. 297:C1062-C1070 |
| ISSN: | 1522-1563 0363-6143 |
| Popis: | Angiotensin II (ANG II) is a major regulator of blood pressure that essentially acts through activation of ANG II type 1 receptor (AT1R) of vascular smooth muscle cells (VSMC). AT1R activates numerous intracellular signaling pathways, including the small G protein RhoA known to control several VSMC functions. Nevertheless, the mechanisms leading to RhoA activation by AT1R are unknown. RhoA activation can result from activation of RhoA exchange factor and/or inhibition of Rho GTPase-activating protein (GAP). Here we hypothesize that a RhoGAP could participate to RhoA activation induced by ANG II in rat aortic VSMC. The knockdown of the RhoGAP p190A by small interfering RNA (siRNA) abolishes the activation of RhoA-Rho kinase pathway induced after 5 min of ANG II (0.1 μM) stimulation in rat aortic VSMC. We then show that AT1R activation induces p190A dephosphorylation and inactivation. In addition, expression of catalytically inactive or phosphoresistant p190A mutants increases the basal activity of RhoA-Rho kinase pathway, whereas phosphomimetic mutant inhibits early RhoA activation by ANG II. Using siRNA and mutant overexpression, we then demonstrate that the tyrosine phosphatase SHP2 is necessary for 1) maintaining p190A basally phosphorylated and activated by the tyrosine kinase c-Abl, and 2) inducing p190A dephosphorylation and RhoA activation in response to AT1R activation. Our work then defines p190A as a new mediator of RhoA activation by ANG II in VSMC. |
| Databáze: | OpenAIRE |
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