Partial phosphorylation of the N-formyl peptide receptor inhibits G protein association independent of arrestin binding.

Bennett TA, Foutz TD, Gurevich VV, Sklar LA, Prossnitz ER
J Biol Chem. 2001 276 (52): 49195-203

PMID: 11602585 · DOI:10.1074/jbc.M106414200

It is now well accepted that G protein-coupled receptors activated by agonist binding become targets for phosphorylation, leading to desensitization of the receptor. Using a series of phosphorylation deficient mutants of the N-formyl peptide receptor (FPR), we have explored the role of phosphorylation on the ability of the receptor to interact with G proteins and arrestins. Using a fluorometric assay in conjunction with solubilized receptors, we demonstrate that phosphorylation of the wild type FPR lowers its affinity for G protein, whereas mutant receptors lacking four potential phosphorylation sites retain their ability to couple to G protein. Phosphorylated mutant receptors lacking only two potential phosphorylation sites are again unable to couple to G protein. Furthermore, whereas stimulated wild type FPR in whole cells colocalizes with arrestin-2, and the solubilized, phosphorylated FPR binds arrestin-2, the stimulated receptors lacking four potential phosphorylation sites display no interaction with arrestin-2. However, the mutant receptors lacking only two potential phosphorylation sites are restored in their ability to bind and colocalize with arrestin-2. Thus, there is a submaximal threshold of FPR phosphorylation that simultaneously results in an inhibition of G protein binding and an induction of arrestin binding. These results are the first to demonstrate that less than maximal levels of receptor phosphorylation can block G protein binding, independent of arrestin binding. We therefore propose that phosphorylation alone may be sufficient to desensitize the FPR in vivo, raising the possibility that for certain G protein-coupled receptors, desensitization may not be the primary function of arrestin.

MeSH Terms (17)

Amino Acid Sequence Animals Arrestin Cell Line Cell Membrane GTP-Binding Proteins Humans Microscopy, Fluorescence Models, Biological Molecular Sequence Data Phosphorylation Protein Binding Protein Structure, Tertiary Receptors, Formyl Peptide Receptors, Immunologic Receptors, Peptide Spectrometry, Fluorescence

Connections (1)

This publication is referenced by other Labnodes entities:

Links