The role of palmitoylation in directing dopamine D1 receptor internalization through selective endocytic routes.
We previously determined that D1 receptors can endocytose through caveolae, a subset of lipid rafts, in addition to internalization via a clathrin-dependent pathway. In this report, we investigated the potential role that palmitoylation might have on directing D1 receptor internalization through either a clathrin or caveolar-dependent route. Through whole cell binding analysis and sucrose gradient fractionation studies, we demonstrated that although palmitoylation of the D1 receptor was not required for agonist-independent localization to caveolae, agonist induced internalization kinetics of a de-palmitoylated D1 receptor were accelerated ∼8-fold in comparison to wild-type D1 receptor and were very similar to that observed for clathrin-dependent D1 receptor internalization. Additionally, inhibition of the clathrin mediated pathway led to significant attenuation in the extent of agonist induced internalization of the de-palmitoylated D1 receptor, suggesting the de-palmitoylated D1 receptor was directed to a clathrin-dependent internalization pathway. Taken together, these data suggest that palmitoylation may be involved in directing agonist-dependent D1 receptor internalization through selective endocytic routes.
Centre for Addiction and Mental Health, Department of Pharmacology, University of Toronto, Toronto, Ontario, Canada.
Michael M C
MM
Kong
Vaneeta
V
Verma
Brian F
BF
O'Dowd
Susan R
SR
George
D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D002966:Clathrin / Q000037:antagonists & inhibitors / Q000378:metabolism; D004705:Endocytosis; D054878:Lipoylation / Q000235:genetics; D017447:Receptors, Dopamine D1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D002966:Clathrin; D017447:Receptors, Dopamine D1
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