| Autor: |
Paradis JS; Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC H3C 1J4, Canada;, Ly S; Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC H3C 1J4, Canada; Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C IJ4, Canada;, Blondel-Tepaz É; Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC H3C 1J4, Canada;, Galan JA; Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC H3C 1J4, Canada; Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC H3C IJ4, Canada;, Beautrait A; Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC H3C 1J4, Canada;, Scott MG; Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France., Enslen H; Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France., Marullo S; Institut Cochin, Inserm U1016, CNRS UMR8104, Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France., Roux PP; Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC H3C 1J4, Canada; Department of Pathology and Cell Biology, Université de Montréal, Montréal, QC H3C IJ4, Canada; philippe.roux@umontreal.ca michel.bouvier@umontreal.ca., Bouvier M; Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC H3C 1J4, Canada; Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3C IJ4, Canada; philippe.roux@umontreal.ca michel.bouvier@umontreal.ca. |
| Abstrakt: |
MAPKs are activated in response to G protein-coupled receptor (GPCR) stimulation and play essential roles in regulating cellular processes downstream of these receptors. However, very little is known about the reciprocal effect of MAPK activation on GPCRs. To investigate possible crosstalk between the MAPK and GPCRs, we assessed the effect of ERK1/2 on the activity of several GPCR family members. We found that ERK1/2 activation leads to a reduction in the steady-state cell-surface expression of many GPCRs because of their intracellular sequestration. This subcellular redistribution resulted in a global dampening of cell responsiveness, as illustrated by reduced ligand-mediated G-protein activation and second-messenger generation as well as blunted GPCR kinases and β-arrestin recruitment. This ERK1/2-mediated regulatory process was observed for GPCRs that can interact with β-arrestins, such as type-2 vasopressin, type-1 angiotensin, and CXC type-4 chemokine receptors, but not for the prostaglandin F receptor that cannot interact with β-arrestin, implicating this scaffolding protein in the receptor's subcellular redistribution. Complementation experiments in mouse embryonic fibroblasts lacking β-arrestins combined with in vitro kinase assays revealed that β-arrestin-2 phosphorylation on Ser14 and Thr276 is essential for the ERK1/2-promoted GPCR sequestration. This previously unidentified regulatory mechanism was observed after constitutive activation as well as after receptor tyrosine kinase- or GPCR-mediated activation of ERK1/2, suggesting that it is a central node in the tonic regulation of cell responsiveness to GPCR stimulation, acting both as an effector and a negative regulator. |
