title: Differential subcellular localization of two dopamine D2 receptor isoforms in transfected NG108-15 cells.
abstract: The dopamine D2 receptor (D2R) is target for antipsychotic drugs and associated with several neuropsychiatric disorders. D2R has a long third cytoplasmic loop and a short carboxyl-terminal cytoplasmic tail. It exists as two alternatively spliced isoforms, termed D2LR and D2SR, which differ in the presence and absence, respectively, of a 29 amino acid insert in the third cytoplasmic loop. To evaluate the differential roles of the two D2R isoforms, we transfected both isoforms into NG108-15 cells and observed their subcellular localization by a confocal laser scanning light microscope. D2SR was predominantly localized at the plasma membrane, whereas D2LR was mostly retained in the perinuclear region around the Golgi apparatus. Using a yeast two hybrid system with a mouse brain cDNA library and coimmunoprecipitation assay, we found that heart-type fatty acid binding protein (H-FABP) interacts with D2LR but not with D2SR. H-FABP is a cytosolic protein involved in binding and transport of fatty acids. Overexpressed H-FABP and endogenous H-FABP were colocalized with the intracellular D2LR in NG108-15 cells. Furthermore, in the rat striatum, H-FABP was detected in the D2R-expressing neurons. From these results, H-FABP is associated with D2LR, and may thereby modulate the subcellular localization and function of D2LR.
authors.affiliation: Department of Pharmacology, Kumamoto University School of Medicine, 2-2-1 Honjo, Kumamoto 860-0811, Japan. yusuket@gpo.kumamoto-u.ac.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Kohji
authors.initials: K
authors.lastname: Fukunaga
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002451:Cell Compartmentation; D003342:Corpus Striatum / Q000166:cytology / Q000378:metabolism; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D008164:Luminescent Proteins / Q000235:genetics; D051379:Mice; D018613:Microscopy, Confocal; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D009447:Neuroblastoma / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017448:Receptors, Dopamine D2 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D014162:Transfection; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C082667:Fabp5 protein, mouse; C086936:Fabp7 protein, mouse; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D008164:Luminescent Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D017448:Receptors, Dopamine D2; D011993:Recombinant Fusion Proteins; C113776:dopamine D2L receptor; C054562:yellow fluorescent protein, Bacteria