GRK2-mediated receptor phosphorylation and Mdm2-mediated ?-arrestin2 ubiquitination drive clathrin-mediated endocytosis of G protein-coupled receptors.
Clathrin-mediated and caveolar endocytic pathways represent the major routes through which G protein-coupled receptors (GPCRs) could be internalized. GPCR kinase 2 (GRK2) and ?-arrestins are representative proteins that mediate the GPCR endocytosis. However, the molecular mechanisms through which GRK2 and ?-arrestin mediate clathrin-mediated and caveolar endocytosis remain unclear. In this ... study, we determined the cellular components and processes that mediate the selective interaction between clathrin/caveolin1 and GRK2/?-arrestins. For this we utilized the following: (i) mutant dopamine D2 receptor and ?2 adrenoceptor in which the potential GRK2 phosphorylation sites were altered and (ii) cells in which clathrin, caveolin1, ?-arrestins, or Mdm2 expression were knocked down. Our results showed that clathrin-mediated endocytosis occurs more rapidly than caveolar endocytosis. Clathrin-mediated endocytosis and the interaction between clathrin and GRK2/?-arrestin2 occurred in a GRK2-mediated receptor phosphorylation-dependent manner. In contrast, caveolar endocytosis and the interaction between caveolin1 and GRK2/?-arrestin2 were independent of receptor phosphorylation status. Mdm2-mediated ubiquitination of ?-arrestin, which occurred in a receptor phosphorylation-dependent manner, was required for the interaction of arrestin with clathrin. Thus, this study shows that GRK2-mediated receptor phosphorylation accompanied by ?-arrestin ubiquitination is a critical cellular event that links GRK2 and ?-arrestins to clathrin-mediated endocytosis.
Mesh Terms:
Caveolin 1, Clathrin, Endocytosis, G-Protein-Coupled Receptor Kinase 2, Gene Knockdown Techniques, HEK293 Cells, Humans, Mutation, Phosphorylation, Protein Binding, Protein Processing, Post-Translational, Proto-Oncogene Proteins c-mdm2, Receptors, Adrenergic, beta-2, Receptors, Dopamine D2, Signal Transduction, Ubiquitination, beta-Arrestin 2
Caveolin 1, Clathrin, Endocytosis, G-Protein-Coupled Receptor Kinase 2, Gene Knockdown Techniques, HEK293 Cells, Humans, Mutation, Phosphorylation, Protein Binding, Protein Processing, Post-Translational, Proto-Oncogene Proteins c-mdm2, Receptors, Adrenergic, beta-2, Receptors, Dopamine D2, Signal Transduction, Ubiquitination, beta-Arrestin 2
Biochem Biophys Res Commun
Date: Dec. 10, 2019
PubMed ID: 32962859
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