title: N-glycans as apical targeting signals in polarized epithelial cells.
abstract: MDCK (Madin-Darby canine kidney) cells represent a good model of polarized epithelium to investigate the signals involved in the apical targeting of proteins. As reported previously, GPI (glycosylphosphatidylinositol) anchors mediate the apical sorting of proteins in polarized epithelial cells through their interaction with lipid rafts. However, using a naturally N-glycosylated and GPI-anchored protein, we found that the GPI anchor does not influence the targeting of the protein. It is, in fact, the N-glycans that signal the protein to the apical surface. In the present review, the role of N-glycans and GPI anchors as apical signals is discussed along with the putative mechanisms involved.
authors.affiliation: School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, U.K. P.Urquhart@leeds.ac.uk
authors.forename: Paula
authors.initials: P
authors.lastname: Urquhart
authors.forename: Susan
authors.initials: S
authors.lastname: Pang
authors.forename: Nigel M
authors.initials: NM
authors.lastname: Hooper
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D002460:Cell Line; D016764:Cell Polarity / Q000502:physiology*; D004150:Dipeptidases / Q000378:metabolism; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D017261:Glycosylphosphatidylinositols; D011134:Polysaccharides; D004150:Dipeptidases; C038937:dipeptidase