Comparative Haploid Genetic Screens Reveal Divergent Pathways in the Biogenesis and Trafficking of Glycophosphatidylinositol-Anchored Proteins

Cell Rep. 2015 Jun 23;11(11):1727-36. doi: 10.1016/j.celrep.2015.05.026. Epub 2015 Jun 11.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD59 Antigens / genetics
  • CD59 Antigens / metabolism
  • Cell Line, Tumor
  • Endoplasmic Reticulum / metabolism*
  • Glycosylphosphatidylinositols / genetics*
  • Glycosylphosphatidylinositols / metabolism
  • Haploidy*
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Molecular Chaperones
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Phosphotransferases / genetics
  • Phosphotransferases / metabolism
  • Prions / metabolism
  • Protein Transport
  • RNA-Binding Proteins


  • CD59 Antigens
  • Glycosylphosphatidylinositols
  • Membrane Proteins
  • Membrane Transport Proteins
  • Molecular Chaperones
  • Nuclear Proteins
  • PGAP2 protein, human
  • PIGF protein, human
  • Prions
  • RNA-Binding Proteins
  • SEC62 protein, human
  • SEC63 protein, human
  • PIGN protein, human
  • Phosphotransferases

Associated data

  • GEO/GSE68796
  • GEO/GSM1681911
  • GEO/GSM1681912
  • GEO/GSM1681913