Angiotensin-II and MARCKS

• Published in: The Journal of biological chemistry Vol. 287; no. 34; pp. 29147 - 29158
• Main Authors: Kalwa, Hermann, Sartoretto, Juliano L., Sartoretto, Simone M., Michel, Thomas
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 17.08.2012
• Subjects: Angiotensin II; Biosensors; Cytoskeleton; Endothelium; Reactive Oxygen Species (ROS); Cytoskeleton; Reactive Oxygen Species (ROS); Angiotensin II; Biosensors; Endothelium
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M112.381517

MARCKS is an actin-binding protein that modulates vascular endothelial cell migration and cytoskeleton signaling (Kalwa, H., and Michel, T. (2011) J. Biol. Chem. 286, 2320–2330). Angiotensin-II is a vasoactive peptide implicated in vascular physiology as well as pathophysiology; the pathways connecting angiotensin-II and cytoskeletal remodeling are incompletely understood. Here we show that MARCKS is expressed in intact arterial preparations, with prominent staining of the endothelium. In endothelial cells, angiotensin-II-promoted MARCKS phosphorylation is abrogated by PEG-catalase, implicating endogenous H2O2 in the angiotensin-II response. Studies using the H2O2 biosensor HyPer2 reveal that angiotensin-II promotes increases in intracellular H2O2. We used a Rac1 FRET biosensor to show that angiotensin-II promotes Rac1 activation that is attenuated by PEG-catalase. siRNA-mediated Rac1 knockdown blocks angiotensin-II-stimulated MARCKS phosphorylation. Cell imaging studies using a phosphoinositide 4,5-bisphosphate (PIP2) biosensor revealed that angiotensin-II PIP2 regulation depends on MARCKS and H2O2. siRNA-mediated knockdown of MARCKS or Rac1 attenuates receptor-mediated activation of the tyrosine kinase c-Abl and disrupts actin fiber formation. These studies establish a critical role for H2O2 in angiotensin-II signaling to the endothelial cytoskeleton in a novel pathway that is critically dependent on MARCKS, Rac1, and c-Abl. Background: The role of the actin-binding protein MARCKS in angiotensin-II signaling is unknown. Results: Biochemical and cell imaging approaches establish that angiotensin-II promotes Rac1- and H2O2-dependent MARCKS phosphorylation and cytoskeleton rearrangement. Conclusion: MARCKS plays a critical role in angiotensin-II signaling. Significance: Angiotensin-II is implicated in vascular physiology and pathophysiology; these studies identify MARCKS as a key determinant of angiotensin-II-modulated responses in the vascular endothelium.