Distinct mechanisms for the endocytosis of muscarinic receptors and Gq/11.
To determine whether the agonist-mediated endocytosis of muscarinic receptors and Gq/11 are mechanistically related events, the internalization of Gq/11 was monitored under conditions established to prevent muscarinic receptor endocytosis. Incubation of SH-SY5Y neuroblastoma cells with oxotremorine-M resulted in the translocation of both muscarinic receptors and Gq/11 into a 'light vesicle' membrane fraction. Although muscarinic receptor translocation was prevented by either the depletion of phosphoinositides or by disruption of clathrin assembly, the endocytosis of Gq/11 was unaffected. These results demonstrate that the agonist-induced internalization of muscarinic receptors and Gq/11 proceed via distinct mechanisms.
Sorensen
S D
SD
Mental Health Research Institute and Department of Pharmacology, University of Michigan, Ann Arbor 48104-1687, USA.
Linseman
D A
DA
Fisher
S K
SK
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004705:Endocytosis / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006982:Hypertonic Solutions / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000378:metabolism*; D000077191:Wortmannin
D000730:Androstadienes; D006982:Hypertonic Solutions; D011976:Receptors, Muscarinic; D019204:GTP-Binding Proteins; D000077191:Wortmannin