title: GPI glycan remodeling by PGAP5 regulates transport of GPI-anchored proteins from the ER to the Golgi.
abstract: Many eukaryotic proteins are attached to the cell surface via glycosylphosphatidylinositol (GPI) anchors. How GPI-anchored proteins (GPI-APs) are trafficked from the endoplasmic reticulum (ER) to the cell surface is poorly understood, but the GPI moiety has been postulated to function as a signal for sorting and transport. Here, we established mutant cells that were selectively defective in transport of GPI-APs from the ER to the Golgi. We identified a responsible gene, designated PGAP5 (post-GPI-attachment to proteins 5). PGAP5 belongs to a dimetal-containing phosphoesterase family and catalyzed the remodeling of the glycan moiety on GPI-APs. PGAP5 catalytic activity is a prerequisite for the efficient exit of GPI-APs from the ER. Our data demonstrate that GPI glycan acts as an ER-exit signal and suggest that glycan remodeling mediated by PGAP5 regulates GPI-AP transport in the early secretory pathway.
authors.affiliation: Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.
authors.forename: Morihisa
authors.initials: M
authors.lastname: Fujita
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Maeda
authors.forename: Moonjin
authors.initials: M
authors.lastname: Ra
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Ryo
authors.initials: R
authors.lastname: Taguchi
authors.forename: Taroh
authors.initials: T
authors.lastname: Kinoshita
mesh_terms: D000818:Animals; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D006801:Humans; D051379:Mice; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*
chemical_list: D006023:Glycoproteins; D017261:Glycosylphosphatidylinositols; D011134:Polysaccharides; D010727:Phosphoric Diester Hydrolases