Abstract
Activation of CXCR2 IL-8 receptor leads to activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and rapid receptor endocytosis. Co-immunoprecipitation and co-localization experiments showed that arrestin and CXCR2 form complexes with components of the ERK1/2 cascade following ligand stimulation. However, in contrast to the activation of the beta2-adrenergic receptor, arrestin was not necessary for ERK1/2 phosphorylation or receptor endocytosis. In contrast, beta-arrestin 1/2 double knockout cells showed greatly enhanced phosphorylation of ERK1/2, as well as phosphorylation of the stress kinases p38 and c-Jun N-terminal protein kinase. The stimulation of stress kinases in arrestin double knockout cells could be attenuated in the presence of diphenylene iodonium (DPI), an inhibitor of the NADPH oxidase, suggesting that reactive oxidant species (ROS) participated in mitogen-activated protein kinase (MAPK) activation. ROS could indeed be detected in IL-8-stimulated beta-arrestin 1/2 knockout cells, and cytoplasmic Rac was translocated to the membrane fraction, which is a prerequisite for oxidant formation. The oxidative burst induced cell death within 6 h of IL-8 stimulation of these cells, which could be prevented in the presence of DPI. These results indicate a novel function for arrestin, which is protection from an excessive oxidative burst, resulting from the sustained stimulation of G-protein-coupled receptors that cause Rac translocation.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Arrestins / physiology*
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Cell Death
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Cell Line
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Cell Membrane / metabolism
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Chemokine CXCL12
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Chemokines, CXC / metabolism
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Cytoplasm / metabolism
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Endocytosis
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Enzyme Inhibitors / pharmacology
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Escherichia coli / metabolism
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Genes, Dominant
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Humans
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Immunoblotting
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Immunoprecipitation
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Interleukin-8 / metabolism
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JNK Mitogen-Activated Protein Kinases / metabolism
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MAP Kinase Signaling System*
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Mice
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Microscopy, Fluorescence
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 3 / metabolism
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NADPH Oxidases / metabolism*
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Onium Compounds / pharmacology
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Oxidants / metabolism
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Oxidative Stress
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Phosphorylation
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Plasmids / metabolism
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Protein Binding
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Protein Transport
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Proto-Oncogene Proteins c-raf / metabolism
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Reactive Oxygen Species
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Receptors, Interleukin-8B / physiology*
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Respiratory Burst
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Subcellular Fractions
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Time Factors
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Transfection
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beta-Arrestin 1
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beta-Arrestins
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p38 Mitogen-Activated Protein Kinases / metabolism
Substances
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ARRB1 protein, human
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Arrb1 protein, mouse
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Arrestins
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CXCL12 protein, human
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Chemokine CXCL12
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Chemokines, CXC
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Cxcl12 protein, mouse
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Enzyme Inhibitors
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Interleukin-8
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Onium Compounds
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Oxidants
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Reactive Oxygen Species
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Receptors, Interleukin-8B
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beta-Arrestin 1
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beta-Arrestins
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diphenyleneiodonium
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NADPH Oxidases
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Proto-Oncogene Proteins c-raf
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JNK Mitogen-Activated Protein Kinases
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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p38 Mitogen-Activated Protein Kinases