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N‐glycosylation of the β 2 adrenergic receptor regulates receptor function by modulating dimerization
Author(s) -
Li Xiaona,
Zhou Mang,
Huang Wei,
Yang Huaiyu
Publication year - 2017
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14098
Subject(s) - receptor , g protein coupled receptor , 5 ht5a receptor , enzyme linked receptor , glycosylation , protease activated receptor 2 , glycan , n linked glycosylation , chemistry , pngase f , biochemistry , signal transduction , extracellular , microbiology and biotechnology , function (biology) , biology , glycoprotein
N‐glycosylation is a common post‐translational modification of G‐protein‐coupled receptors ( GPCR s). However, it remains unknown how N‐glycosylation affects GPCR signaling. β 2 adrenergic receptor (β 2 AR ) has three N‐glycosylation sites: Asn6, Asn15 at the N‐terminus, and Asn187 at the second extracellular loop ( ECL 2). Here, we show that deletion of the N‐glycan did not affect receptor expression and ligand binding. Deletion of the N‐glycan at the N‐terminus rather than Asn187 showed decreased effects on isoproterenol‐promoted G‐protein‐dependent signaling, β‐arrestin2 recruitment, and receptor internalization. Both N6Q and N15Q showed decreased receptor dimerization, while N187Q did not influence receptor dimerization. As decreased β 2 AR homodimer accompanied with reduced efficiency for receptor function, we proposed that the N‐glycosylation of β 2 AR regulated receptor function by influencing receptor dimerization. To verify this hypothesis, we further paid attention to the residues at the dimerization interface. Studies of Lys60 and Glu338, two residues at the receptor dimerization interface, exhibited that the K60A/E338A showed decreased β 2 AR dimerization and its effects on receptor signaling were similar to N6Q and N15Q, which further supported the importance of receptor dimerization for receptor function. This work provides new insights into the relationship among glycosylation, dimerization, and function of GPCR s. Enzymes Peptide‐N‐glycosidase F (PNGase F, EC 3.2.2.11 ); endo‐β‐N‐acetylglucosaminidase A (Endo‐A, EC 3.2.1.96 ).