D(2)-Dopamine receptors target regulator of G protein signaling 9-2 to detergent-resistant membrane fractions.
Detergent-resistant membranes (DRM) are thought to contain structures such as lipid rafts that are involved in compartmentalizing cell membranes. We report that the majority of D(2)-dopamine receptors (D(2)R) expressed endogenously in mouse striatum or expressed in immortalized cell-lines is found in DRM. In addition, exogenous co-expression of D(2)R in a cell line shifted the expression of regulator of G protein signaling 9-2 (RGS9-2) into DRM. RGS9-2 is a protein that is highly enriched in the striatum and specifically regulates striatal D(2)R. In the striatum, RGS9-2 is mostly associated with DRMs but when expressed in cell lines, RGS9-2 is present in the soluble cytoplasmic fraction. In contrast, the majority of mu opioid receptors and delta opioid receptors are found in detergent-soluble membrane and there was no shift of RGS9-2 into DRM after co-expression of mu opioid receptor. These data suggest that the targeting of RGS9-2 to DRM in the striatum is mediated by D(2)R and that DRM is involved in the formation of a D(2)R signaling complex. D(2)R-mediated targeting of RGS9-2 to DRM was blocked by the deletion of the RGS9-2 DEP domain or by a point mutation that abolishes the GTPase accelerating protein function of RGS9-2.
Department of Biomedical and Pharmacological Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island, USA.
Jeremy
J
Celver
Meenakshi
M
Sharma
Abraham
A
Kovoor
D015153:Blotting, Western; D001923:Brain Chemistry; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects*; D003342:Corpus Striatum / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D003902:Detergents / Q000494:pharmacology*; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000737:chemistry; D009154:Mutation / Q000235:genetics; D017830:Octoxynol; D020710:RGS Proteins / Q000235:genetics / Q000502:physiology*; D017448:Receptors, Dopamine D2 / Q000187:drug effects* / Q000235:genetics; D017465:Receptors, Opioid, delta / Q000235:genetics; D017450:Receptors, Opioid, mu / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects*; D012995:Solubility; D014162:Transfection
D018076:DNA, Complementary; D003902:Detergents; C490611:GNB5 protein, human; D044387:GTP-Binding Protein beta Subunits; D008565:Membrane Proteins; D020710:RGS Proteins; D017448:Receptors, Dopamine D2; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; C116925:regulator of g-protein signaling 9; D017830:Octoxynol