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Lipid rafts and membrane cholesterol are involved in regulating D2 dopamine receptor signaling
Author(s) -
Hazelwood Lisa A,
Romanelli Robert J,
Free R Benjamin,
Roof Rebecca A,
Javitch Jonathan A,
Neve Kim A,
Sibley David R
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.584.1
Subject(s) - lipid raft , microbiology and biotechnology , g protein coupled receptor , sphingolipid , chemistry , caveolin , hek 293 cells , signal transduction , receptor , g protein , cholesterol , caveolae , biology , biochemistry
Lipid rafts are specialized membrane microdomains enriched in cholesterol, sphingolipids and caveolin. They are important in the organization of GPCR‐protein complexes and the regulation of signaling. Given the emerging significance of lipids with respect to GPCR structure and activation, we have investigated the role of lipid rafts and membrane cholesterol on D 2 dopamine receptor (DAR) localization and function. Sucrose density fractionation revealed that D 2 DARs are enriched in lipid rafts from both striatum and transfected HEK293 cells. Depletion of membrane cholesterol with methyl‐β‐cyclodextrin (MCD) diminished cell‐surface D 2 DAR expression in HEK293T cells by approximately 75% without altering total receptor number. MCD treatment also completely abolished DA signaling at the D 2 DAR. Importantly, when D 2 DAR transfections were titrated to achieve surface expression values comparable to MCD‐treatment, a DA‐dependent decrease in cAMP was still observed. Diminished signaling of Gi/o‐coupled muscarinic receptors was also observed following MCD‐treatments. Notably, MCD‐treatment did not inhibit Gs‐linked D 1 DAR function or forskolin‐stimulated cAMP accumulation. These results suggest that lipid rafts and/or membrane cholesterol are critical for D 2 DAR signaling.