Agonist-dependent delivery of M(2) muscarinic acetylcholine receptors to the cell surface after pertussis toxin treatment.
The internalization of the M(2) muscarinic cholinergic receptor (mAChR) proceeds through an atypical pathway that is independent of arrestin and clathrin function and shows a unique sensitivity to dynamin when the receptor is expressed in human embryonic kidney 293 cells. In this report we demonstrate that the internalization of the M(2) mAChR was modulated by activation of heterotrimeric G proteins, because treatment with pertussis toxin, which ADP-ribosylates G proteins of the G(i/o) family, caused a significant delay in the onset of internalization of the M(2) mAChR. The effects of pertussis toxin could not be explained by alteration of the agonist-dependent phosphorylation of the M(2) mAChR. The modulation of internalization by pertussis toxin was revealed to be due to recruitment of intracellular receptors to the cell surface upon agonist treatment. Pretreatment with pertussis toxin also greatly increased both the rate and extent of recovery of M(2) mAChRs to the cell surface after agonist-mediated internalization. These results demonstrate a novel aspect involved in the regulation of GPCRs. As with the tightly controlled internalization of GPCRs, the delivery of GPCRs to the cell surface is also highly regulated.
Roseberry
A G
AG
Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, Illinois, USA.
Bünemann
M
M
Elavunkal
J
J
Hosey
M M
MM
D001692:Biological Transport / Q000187:drug effects; D020126:Brefeldin A / Q000494:pharmacology; D002478:Cells, Cultured; D004347:Drug Interactions; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D018721:Muscarinic Agonists / Q000494:pharmacology*; D037342:Pertussis Toxin; D010766:Phosphorylation / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D043585:Receptor, Muscarinic M2; D011956:Receptors, Cell Surface / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D018721:Muscarinic Agonists; D011500:Protein Synthesis Inhibitors; D043585:Receptor, Muscarinic M2; D011956:Receptors, Cell Surface; D011976:Receptors, Muscarinic; D010566:Virulence Factors, Bordetella; D020126:Brefeldin A; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020962:Heterotrimeric GTP-Binding Proteins