Abstract
Beta-arrestins-1 and 2 are known to play important roles in desensitization of membrane receptors and facilitation of signal transduction pathways. It has been previously shown that beta-arrestins are required for signal termination, internalization, and ERK1/2 activation downstream of protease-activated-receptor-2 (PAR-2), but it is unclear whether they are functionally redundant or mediate specific events. Here, we demonstrate that in mouse embryonic fibroblasts (MEFs) from beta-arrestin-1/2 knockout mice, G alpha q signaling by PAR-2, as measured by mobilization of intracellular Ca(2+), is prolonged. Only expression of beta-arrestin-1 shortened the signal duration, whereas either beta-arrestin-1 or 2 was able to restore PKC-induced receptor desensitization. Beta-arrestin-1 also mediated early, while beta-arrestin-2 mediated delayed, receptor internalization and membrane-associated ERK1/2 activation. While beta-arrestin-1 colocalized with a lysosomal marker (LAMP-1), beta-arrestin-2 did not, suggesting a specific role for beta-arrestin-1 in lysosomal receptor degradation. Together, these data suggest distinct temporal and functional roles for beta-arrestins in PAR-2 signaling, desensitization, and internalization.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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Arrestins / deficiency
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Arrestins / genetics
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Arrestins / metabolism*
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CHO Cells
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Calcium Signaling* / drug effects
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Cell Line, Tumor
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Cricetinae
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Cricetulus
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Embryo, Mammalian / cytology
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Embryo, Mammalian / metabolism
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Endocytosis* / drug effects
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Enzyme Activation
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Exocytosis
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Fibroblasts / drug effects
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Fibroblasts / enzymology
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Fibroblasts / metabolism*
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Green Fluorescent Proteins / genetics
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Green Fluorescent Proteins / metabolism
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Humans
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Kinetics
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Lysosomal-Associated Membrane Protein 1 / metabolism
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Lysosomes / metabolism
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Mice
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Mice, Knockout
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Mitogen-Activated Protein Kinase 1 / metabolism*
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Mitogen-Activated Protein Kinase 3 / metabolism*
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Oligopeptides / pharmacology
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Protein Isoforms / metabolism
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Protein Kinase C / metabolism
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Receptor, PAR-2 / agonists
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Receptor, PAR-2 / genetics
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Receptor, PAR-2 / metabolism*
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Recombinant Fusion Proteins / metabolism
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Transfection
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Trypsin / metabolism
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beta-Arrestin 1
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beta-Arrestin 2
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beta-Arrestins
Substances
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2-furoyl-LIGRLO-amide
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ARRB1 protein, human
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ARRB2 protein, human
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Arrb1 protein, mouse
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Arrb2 protein, mouse
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Arrestins
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Lysosomal-Associated Membrane Protein 1
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Oligopeptides
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Protein Isoforms
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Receptor, PAR-2
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Recombinant Fusion Proteins
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beta-Arrestin 1
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beta-Arrestin 2
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beta-Arrestins
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Green Fluorescent Proteins
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Protein Kinase C
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3
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Trypsin