title: N-glycosylation of the human granulocyte-macrophage colony-stimulating factor receptor alpha subunit is essential for ligand binding and signal transduction.
abstract: The alpha subunit of the receptor for human granulocyte-macrophage colony-stimulating factor (GM-CSF) is a glycoprotein containing 11 potential N-glycosylation sites in the extracellular domain. We examined the role of N-glycosylation on alpha subunit membrane localization and function. Tunicamycin, an N-glycosylation inhibitor, markedly inhibited GM-CSF binding, GM-CSF-induced deoxyglucose uptake, and protein tyrosine phosphorylation in HL-60(eos) cells but did not affect cell surface expression of the alpha subunit as detected by an anti-alpha subunit monoclonal antibody. In COS cells expressing the alpha subunit and treated with tunicamycin, N-unglycosylated alpha subunit was expressed and transported to the cell surface but was not capable of binding GM-CSF. High affinity binding in COS cells expressing both alpha and beta subunits was also blocked by tunicamycin treatment. These studies indicate that N-linked oligosaccharides are essential for alpha subunit ligand binding and signaling by the human GM-CSF receptor.
authors.affiliation: Graduate Program in Molecular Biology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
authors.forename: D X
authors.initials: DX
authors.lastname: Ding
authors.forename: J C
authors.initials: JC
authors.lastname: Vera
authors.forename: M L
authors.initials: ML
authors.lastname: Heaney
authors.forename: D W
authors.initials: DW
authors.lastname: Golde
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D006031:Glycosylation / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D018922:HL-60 Cells; D006801:Humans; D007700:Kinetics; D008024:Ligands; D046911:Macromolecular Substances; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014162:Transfection; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D008024:Ligands; D046911:Macromolecular Substances; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D011994:Recombinant Proteins; D014415:Tunicamycin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor