University of Oulu

Goth, C. K., Tuhkanen, H. E., Khan, H., Lackman, J. J., Wang, S., Narimatsu, Y., … Petäjä-Repo, U. E. (2017). Site-specificO-Glycosylation by PolypeptideN-Acetylgalactosaminyltransferase 2 (GalNAc-transferase T2) Co-regulates β1-Adrenergic Receptor N-terminal Cleavage. Journal of Biological Chemistry, 292(11), 4714–4726.

Site-specific O-glycosylation by polypeptide N-acetylgalactosaminyltransferase 2 (GalNAc-transferase T2) co-regulates β1-adrenergic receptor N-terminal cleavage

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Author: Goth, Christoffer K.1; Tuhkanen, Hanna E.2; Khan, Hamayun2;
Organizations: 1Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark
2Medical Research Center Oulu, Research Unit of Biomedicine, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland
3Department of Clinical Biochemistry, Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen Ø, Denmark
4Centre for Blood Research, Department of Oral Biological and Medical Sciences, and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
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Language: English
Published: American Society for Biochemistry and Molecular Biology, 2017
Publish Date: 2019-12-05


The β1-adrenergic receptor (β₁AR) is a G protein-coupled receptor (GPCR) and the predominant adrenergic receptor subtype in the heart, where it mediates cardiac contractility and the force of contraction. Although it is the most important target for β-adrenergic antagonists, such as β-blockers, relatively little is yet known about its regulation. We have shown previously that β₁AR undergoes constitutive and regulated N-terminal cleavage participating in receptor down-regulation and, moreover, that the receptor is modified by O-glycosylation. Here we demonstrate that the polypeptide GalNAc-transferase 2 (GalNAc-T2) specifically O-glycosylates β₁AR at five residues in the extracellular N terminus, including the Ser-49 residue at the location of the common S49G single-nucleotide polymorphism. Using in vitro O-glycosylation and proteolytic cleavage assays, a cell line deficient in O-glycosylation, GalNAc-T-edited cell line model systems, and a GalNAc-T2 knock-out rat model, we show that GalNAc-T2 co-regulates the metalloproteinase-mediated limited proteolysis of β₁AR. Furthermore, we demonstrate that impaired O-glycosylation and enhanced proteolysis lead to attenuated receptor signaling, because the maximal response elicited by the βAR agonist isoproterenol and its potency in a cAMP accumulation assay were decreased in HEK293 cells lacking GalNAc-T2. Our findings reveal, for the first time, a GPCR as a target for co-regulatory functions of site-specific O-glycosylation mediated by a unique GalNAc-T isoform. The results provide a new level of β₁AR regulation that may open up possibilities for new therapeutic strategies for cardiovascular diseases.

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Series: Journal of biological chemistry
ISSN: 0021-9258
ISSN-E: 1083-351X
ISSN-L: 0021-9258
Volume: 292
Issue: 11
Pages: 4714 - 4726
DOI: 10.1074/jbc.M116.730614
Type of Publication: A1 Journal article – refereed
Field of Science: 3111 Biomedicine
Funding: This work was supported by the Danish Research Councils (including a Sapere Aude Research Talent Grant to K. T. S.), a program of excellence grant from the University of Copenhagen, the Novo Nordisk Foundation, Danish National Research Foundation Grant DNRF107 (to H. C.), the Neye Foundation (to C. G.), and the MRC Oulu and Magnus Ehrnrooth Foundation (to U. E. P.-R.).
Copyright information: This research was originally published in the Journal of Biological Chemistry. Goth, C. K., Tuhkanen, H. E., Khan, H., Lackman, J. J., Wang, S., Narimatsu, Y., … Petäjä-Repo, U. E.. Site-specific O-Glycosylation by Polypeptide N-Acetylgalactosaminyltransferase 2 (GalNAc-transferase T2) Co-regulates β1-Adrenergic Receptor N-terminal Cleavage. J. Biol. Chem. 2017; 292(11), 4714–4726. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.