title: Comparative Haploid Genetic Screens Reveal Divergent Pathways in the Biogenesis and Trafficking of Glycophosphatidylinositol-Anchored Proteins.
abstract: Glycophosphatidylinositol-anchored proteins (GPI-APs) play essential roles in physiology, but their biogenesis and trafficking have not been systematically characterized. Here, we took advantage of the recently available haploid genetics approach to dissect GPI-AP pathways in human cells using prion protein (PrP) and CD59 as model molecules. Our screens recovered a large number of common and unexpectedly specialized factors in the GPI-AP pathways. PIGN, PGAP2, and PIGF, which encode GPI anchor-modifying enzymes, were selectively isolated in the CD59 screen, suggesting that GPI anchor composition significantly influences the biogenesis of GPI-APs in a substrate-dependent manner. SEC62 and SEC63, which encode components of the ER-targeting machinery, were selectively recovered in the PrP screen, indicating that they do not constitute a universal route for the biogenesis of mammalian GPI-APs. Together, these comparative haploid genetic screens demonstrate that, despite their similarity in overall architecture and subcellular localization, GPI-APs follow markedly distinct biosynthetic and trafficking pathways.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Davis
authors.affiliation: Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA.
authors.forename: Jihye
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.
authors.forename: Bridget L
authors.initials: BL
authors.lastname: Menasche
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.
authors.forename: Jacob
authors.initials: J
authors.lastname: Sheppard
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA.
authors.forename: Xuedong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA.
authors.forename: Aik-Choon
authors.initials: AC
authors.lastname: Tan
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA. Electronic address: jingshi.shen@colorado.edu.
authors.forename: Jingshi
authors.initials: J
authors.lastname: Shen
mesh_terms: D018957:CD59 Antigens / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000235:genetics* / Q000378:metabolism; D006238:Haploidy; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D018832:Molecular Chaperones; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism; D011328:Prions / Q000378:metabolism; D021381:Protein Transport; D016601:RNA-Binding Proteins
chemical_list: D018957:CD59 Antigens; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins; C484441:PGAP2 protein, human; C098069:PIGF protein, human; D011328:Prions; D016601:RNA-Binding Proteins; C103676:SEC62 protein, human; C487464:SEC63 protein, human; C561296:PIGN protein, human; D010770:Phosphotransferases