title: Distinct CCR7 glycosylation pattern shapes receptor signaling and endocytosis to modulate chemotactic responses.
abstract: The homeostatic chemokines CCL19 and CCL21 and their common cognate chemokine receptor CCR7 orchestrate immune cell trafficking by eliciting distinct signaling pathways. Here, we demonstrate that human CCR7 is N-glycosylated on 2 specific residues in the N terminus and the third extracellular loop. Conceptually, CCR7 glycosylation adds steric hindrance to the receptor N terminus and extracellular loop 3, acting as a "swinging door" to regulate receptor sensitivity and cell migration. We found that freshly isolated human B cells, as well as expanded T cells, but not naïve T cells, express highly sialylated CCR7. Moreover, we identified that human dendritic cells imprint T cell migration toward CCR7 ligands by secreting enzymes that deglycosylate CCR7, thereby boosting CCR7 signaling on T cells, permitting enhanced T cell locomotion, while simultaneously decreasing receptor endocytosis. In addition, dendritic cells proteolytically convert immobilized CCL21 to a soluble form that is more potent in triggering chemotactic movement and does not desensitize the receptor. Furthermore, we demonstrate that soluble CCL21 functionally resembles neither the CCL19 nor the CCL21 phenotype but acts as a chemokine with unique features. Thus, we advance the concept of dendritic cell-dependent generation of micromilieus and lymph node conditioning by demonstrating a novel layer of CCR7 regulation through CCR7 sialylation. In summary, we demonstrate that leukocyte subsets express distinct patterns of CCR7 sialylation that contribute to receptor signaling and fine-tuning chemotactic responses.
authors.affiliation: Biotechnology Institute Thurgau at the University of Konstanz, University of Konstanz, Konstanz, Germany;
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hauser
authors.affiliation: Biotechnology Institute Thurgau at the University of Konstanz, University of Konstanz, Konstanz, Germany;
authors.forename: Ilona
authors.initials: I
authors.lastname: Kindinger
authors.affiliation: Biotechnology Institute Thurgau at the University of Konstanz, University of Konstanz, Konstanz, Germany;
authors.forename: Julia M
authors.initials: JM
authors.lastname: Laufer
authors.affiliation: Department of Chemistry, Chair of Organic Chemistry/Bioorganic Chemistry, University of Konstanz, Konstanz, Germany; and.
authors.forename: Anne-Katrin
authors.initials: AK
authors.lastname: Späte
authors.affiliation: Biotechnology Institute Thurgau at the University of Konstanz, University of Konstanz, Konstanz, Germany;
authors.forename: Delia
authors.initials: D
authors.lastname: Bucher
authors.affiliation: Biotechnology Institute Thurgau at the University of Konstanz, University of Konstanz, Konstanz, Germany;
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Vanes
authors.affiliation: Klinikum Konstanz, Konstanz, Germany.
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Krueger
authors.affiliation: Department of Chemistry, Chair of Organic Chemistry/Bioorganic Chemistry, University of Konstanz, Konstanz, Germany; and.
authors.forename: Valentin
authors.initials: V
authors.lastname: Wittmann
authors.affiliation: Biotechnology Institute Thurgau at the University of Konstanz, University of Konstanz, Konstanz, Germany; daniel.legler@bitg.ch.
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Legler
mesh_terms: D001216:Asparagine / Q000378:metabolism; D001665:Binding Sites; D002450:Cell Communication; D002460:Cell Line; D054415:Chemokine CCL19; D002633:Chemotaxis; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism; D004705:Endocytosis; D006031:Glycosylation; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D050505:Mutant Proteins / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry; D054400:Receptors, CCR7 / Q000378:metabolism*; D015398:Signal Transduction; D012995:Solubility; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism
chemical_list: C515460:CCL19 protein, human; D054415:Chemokine CCL19; D055767:Immobilized Proteins; D008024:Ligands; D050505:Mutant Proteins; D011134:Polysaccharides; D054400:Receptors, CCR7; D001216:Asparagine; D019158:N-Acetylneuraminic Acid
keywords: CCL19/21; cell migration; dendritic–T cell interaction; internalization; signal transduction