Regulation of G protein-coupled receptor kinases by caveolin.
G protein-coupled receptor kinases (GRKs) have been principally characterized by their ability to phosphorylate and desensitize G protein-coupled receptors. However, recent studies suggest that GRKs may have more diverse protein/protein interactions in cells. Based on the identification of a consensus caveolin binding motif within the pleckstrin homology domain of GRK2, ... we tested the direct binding of purified full-length GRK2 to various glutathione S-transferase-caveolin-1 fusion proteins, and we discovered a specific interaction of GRK2 with the caveolin scaffolding domain. Interestingly, analysis of GRK1 and GRK5, which lack a pleckstrin homology domain, revealed in vitro binding properties similar to those of GRK2. Maltose-binding protein caveolin and glutathione S-transferase-GRK fusion proteins were used to map overlapping regions in the N termini of both GRK2 and GRK5 that appear to mediate conserved GRK/caveolin interactions. In vivo association of GRK2 and caveolin was suggested by co-fractionation of GRK2 with caveolin in A431 and NIH-3T3 cells and was further supported by co-immunoprecipitation of GRK2 and caveolin in COS-1 cells. Functional significance for the GRK/caveolin interaction was demonstrated by the potent inhibition of GRK-mediated phosphorylation of both receptor and peptide substrates by caveolin-1 and -3 scaffolding domain peptides. These data reveal a novel mode for the regulation of GRKs that is likely to play an important role in their cellular function.
Mesh Terms:
Amino Acid Sequence, Caveolin 1, Caveolins, Cell Line, Cyclic AMP-Dependent Protein Kinases, Eye Proteins, G-Protein-Coupled Receptor Kinase 1, G-Protein-Coupled Receptor Kinase 5, Membrane Proteins, Molecular Sequence Data, Peptide Fragments, Phosphorylation, Precipitin Tests, Protein Binding, Protein Kinases, Protein-Serine-Threonine Kinases, Receptor Protein-Tyrosine Kinases, Recombinant Fusion Proteins, beta-Adrenergic Receptor Kinases
Amino Acid Sequence, Caveolin 1, Caveolins, Cell Line, Cyclic AMP-Dependent Protein Kinases, Eye Proteins, G-Protein-Coupled Receptor Kinase 1, G-Protein-Coupled Receptor Kinase 5, Membrane Proteins, Molecular Sequence Data, Peptide Fragments, Phosphorylation, Precipitin Tests, Protein Binding, Protein Kinases, Protein-Serine-Threonine Kinases, Receptor Protein-Tyrosine Kinases, Recombinant Fusion Proteins, beta-Adrenergic Receptor Kinases
J. Biol. Chem.
Date: Mar. 26, 1999
PubMed ID: 10085129
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