title: N-glycans and glycosylphosphatidylinositol-anchor act on polarized sorting of mouse PrP(C) in Madin-Darby canine kidney cells.
abstract: The cellular prion protein (PrP(C)) plays a fundamental role in prion disease. PrP(C) is a glycosylphosphatidylinositol (GPI)-anchored protein with two variably occupied N-glycosylation sites. In general, GPI-anchor and N-glycosylation direct proteins to apical membranes in polarized cells whereas the majority of mouse PrP(C) is found in basolateral membranes in polarized Madin-Darby canine kidney (MDCK) cells. In this study we have mutated the first, the second, and both N-glycosylation sites of PrP(C) and also replaced the GPI-anchor of PrP(C) by the Thy-1 GPI-anchor in order to investigate the role of these signals in sorting of PrP(C) in MDCK cells. Cell surface biotinylation experiments and confocal microscopy showed that lack of one N-linked oligosaccharide leads to loss of polarized sorting of PrP(C). Exchange of the PrP(C) GPI-anchor for the one of Thy-1 redirects PrP(C) to the apical membrane. In conclusion, both N-glycosylation and GPI-anchor act on polarized sorting of PrP(C), with the GPI-anchor being dominant over N-glycans.
authors.affiliation: Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Berta
authors.initials: B
authors.lastname: Puig
authors.forename: Hermann C
authors.initials: HC
authors.lastname: Altmeppen
authors.forename: Dana
authors.initials: D
authors.lastname: Thurm
authors.forename: Markus
authors.initials: M
authors.lastname: Geissen
authors.forename: Catharina
authors.initials: C
authors.lastname: Conrad
authors.forename: Thomas
authors.initials: T
authors.lastname: Braulke
authors.forename: Markus
authors.initials: M
authors.lastname: Glatzel
mesh_terms: D000818:Animals; D019921:Biotinylation; D002460:Cell Line; D004285:Dogs; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D011134:Polysaccharides / Q000378:metabolism*; D018621:PrPC Proteins / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D017261:Glycosylphosphatidylinositols; D011134:Polysaccharides; D018621:PrPC Proteins