title: N-linked Glycosylation on the N-terminus of the dopamine D2 and D3 receptors determines receptor association with specific microdomains in the plasma membrane.
abstract: Numerous G protein-coupled receptors (GPCRs) are glycosylated at extracellular regions. The regulatory roles of glycosylation on receptor function vary across receptor types. In this study, we used the dopamine D₂and D₃receptors as an experimental model to understand the underlying principles governing the functional roles of glycosylation. We used the pharmacological inhibitor, tunicamycin, to inhibit glycosylation, generated chimeric D₂and D₃receptors by swapping their respective N-termini, and produced the glycosylation site mutant D₂and D₃receptors to study the roles of glycosylation on receptor functions, including cell surface expression, signaling, and internalization through specific microdomains. Our results demonstrate that glycosylation on the N-terminus of the D₃ receptor is involved in the development of desensitization and proper cell surface expression. In addition, glycosylation on the N-terminus mediates the internalization of D₂and D₃receptors within the caveolae and clathrin-coated pit microdomains of the plasma membrane, respectively, by regulating receptor interactions with caveolin-1 and clathrin. In conclusion, this study shows for the first time that glycosylation on the N-terminus of GPCRs is involved in endocytic pathway selection through specific microdomains. These data suggest that changes in the cellular environment that influence posttranslational modification could be an important determinant of intracellular GPCR trafficking.
authors.affiliation: Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea.
authors.forename: Chengchun
authors.initials: C
authors.lastname: Min
authors.affiliation: Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea.
authors.forename: Mei
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea.
authors.forename: Shuohan
authors.initials: S
authors.lastname: Guo
authors.affiliation: Department of Pharmacology, College of Medicine, Konkuk University, Seoul, Republic of Korea.
authors.forename: Kyoung-Ja
authors.initials: KJ
authors.lastname: Kwon
authors.affiliation: Department of Pharmacology, College of Medicine, Konkuk University, Seoul, Republic of Korea.
authors.forename: Chan Young
authors.initials: CY
authors.lastname: Shin
authors.affiliation: Department of Forensic Medicine, College of Medicine, Chonnam National University, Gwang-Ju, Republic of Korea.
authors.forename: Hyeong-Suk
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Medicinal Chemistry, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea.
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Cheon
authors.affiliation: Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea. Electronic address: kmkim@jnu.ac.kr.
authors.forename: Kyeong-Man
authors.initials: KM
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D004705:Endocytosis; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D021962:Membrane Microdomains / Q000737:chemistry*; D008969:Molecular Sequence Data; D017448:Receptors, Dopamine D2 / Q000737:chemistry* / Q000378:metabolism; D050637:Receptors, Dopamine D3 / Q000737:chemistry* / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: C581293:DRD2 protein, human; C493593:DRD3 protein, human; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D014415:Tunicamycin
keywords: MβCD; PNGaseF; Post-translational modification