title: Glycosylphosphatidylinositol-anchored proteins: Membrane organization and transport.
abstract: Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are a class of membrane proteins containing a soluble protein attached by a conserved glycolipid anchor to the external leaflet of the plasma membrane. In polarized epithelial cells, GPI-APs are predominantly sorted to the apical surface in the trans-Golgi network (TGN) by clustering in sphingolipid- and cholesterol-dependent microdomains (or rafts), which have been proposed to act as apical sorting platforms. Recent data indicate that the mechanisms of GPI-AP sorting, occurring in the Golgi, control both the membrane transport of GPI-APs and their specific activity at the apical surface of fully polarized epithelial cells. Here, we discuss the most recent findings and the factors regulating apical sorting of GPI-APs at the Golgi in polarized epithelial cells. We also underline the differences in the plasma membrane organization of GPI-APs between polarized and non-polarized cells supporting the existence of various mechanisms that control GPI-AP organization in different cell types.
authors.affiliation: Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France. Electronic address: zurzolo@pasteur.fr.
authors.forename: Chiara
authors.initials: C
authors.lastname: Zurzolo
authors.affiliation: Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Simons
mesh_terms: D002462:Cell Membrane / Q000737:chemistry; D016764:Cell Polarity; D002784:Cholesterol / Q000737:chemistry / Q000378:metabolism; D004847:Epithelial Cells; D017261:Glycosylphosphatidylinositols / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D021962:Membrane Microdomains / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D021381:Protein Transport; D021601:trans-Golgi Network / Q000737:chemistry / Q000378:metabolism
chemical_list: D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D002784:Cholesterol
keywords: Apical sorting; Cholesterol-dependent domains; GPI-anchored proteins; Lipid–protein interaction; Nanoclusters; Oligomerization