Abstract
Invadosomes are actin-rich membrane protrusions that degrade the extracellular matrix to drive tumor cell invasion. Key players in invadosome formation are c-Src and Rho family GTPases. Invadosomes can reassemble into circular rosette-like superstructures, but the underlying signaling mechanisms remain obscure. Here we show that Src-induced invadosomes in human melanoma cells (A375M and MDA-MB-435) undergo rapid remodeling into dynamic extracellular matrix-degrading rosettes by distinct G protein-coupled receptor agonists, notably lysophosphatidic acid (LPA; acting through the LPA1 receptor) and endothelin. Agonist-induced rosette formation is blocked by pertussis toxin, dependent on PI3K activity and accompanied by localized production of phosphatidylinositol 3,4,5-trisphosphate, whereas MAPK and Ca(2+) signaling are dispensable. Using FRET-based biosensors, we show that LPA and endothelin transiently activate Cdc42 through Gi, concurrent with a biphasic decrease in Rac activity and differential effects on RhoA. Cdc42 activity is essential for rosette formation, whereas G12/13-mediated RhoA-ROCK signaling suppresses the remodeling process. Our results reveal a Gi-mediated Cdc42 signaling axis by which G protein-coupled receptors trigger invadosome remodeling, the degree of which is dictated by the Cdc42-RhoA activity balance.
Keywords:
CDC42; G protein-coupled receptor (GPCR); Rac (Rac GTPase); Rho (Rho GTPase); biosensor; calcium intracellular release; fluorescence resonance energy transfer (FRET); imaging; invadopodia; phosphatidylinositide 3-kinase (PI 3-kinase).
© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Biomarkers / metabolism
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Cell Line, Tumor
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Endothelins / metabolism*
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Extracellular Matrix / metabolism
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Extracellular Matrix / pathology
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Fluorescence Resonance Energy Transfer
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Humans
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Hydrolysis
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Luminescent Proteins / genetics
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Luminescent Proteins / metabolism
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Lysophospholipids / metabolism*
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Melanoma / enzymology
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Melanoma / metabolism*
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Melanoma / pathology
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Microscopy, Confocal
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Microscopy, Fluorescence
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Neoplasm Proteins / agonists
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Neoplasm Proteins / antagonists & inhibitors
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Neoplasm Proteins / genetics
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Neoplasm Proteins / metabolism
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Podosomes / enzymology
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Podosomes / metabolism*
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Podosomes / pathology
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RNA Interference
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Receptors, G-Protein-Coupled / antagonists & inhibitors
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Receptors, G-Protein-Coupled / genetics
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Receptors, G-Protein-Coupled / metabolism
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Receptors, Lysophosphatidic Acid / agonists*
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Receptors, Lysophosphatidic Acid / antagonists & inhibitors
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Receptors, Lysophosphatidic Acid / genetics
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Receptors, Lysophosphatidic Acid / metabolism
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Time-Lapse Imaging
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cdc42 GTP-Binding Protein / agonists*
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cdc42 GTP-Binding Protein / antagonists & inhibitors
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cdc42 GTP-Binding Protein / genetics
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cdc42 GTP-Binding Protein / metabolism
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rac1 GTP-Binding Protein / agonists
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rac1 GTP-Binding Protein / antagonists & inhibitors
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rac1 GTP-Binding Protein / genetics
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rac1 GTP-Binding Protein / metabolism*
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rhoA GTP-Binding Protein / antagonists & inhibitors
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rhoA GTP-Binding Protein / genetics
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rhoA GTP-Binding Protein / metabolism
Substances
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Biomarkers
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Endothelins
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GPR26 protein, human
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Luminescent Proteins
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Lysophospholipids
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Neoplasm Proteins
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RAC1 protein, human
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Receptors, G-Protein-Coupled
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Receptors, Lysophosphatidic Acid
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Recombinant Proteins
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RHOA protein, human
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cdc42 GTP-Binding Protein
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rac1 GTP-Binding Protein
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rhoA GTP-Binding Protein
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lysophosphatidic acid