title: 1,10-Phenanthroline inhibits glycosylphosphatidylinositol anchoring by preventing phosphoethanolamine addition to glycosylphosphatidylinositol anchor precursors.
abstract: The glycosylphosphatidylinositol (GPI) moiety is widely used to anchor a functionally diverse group of proteins to the plasma membrane of eukaryotes. In mammals, the predominant glycan structure of the GPI anchor consists of EthN-P-Man-Man-(EthN-P)Man-GlcN attached to an inositol phospholipid. In a smaller percentage of anchors analyzed to date, a third P-EthN group linked to the middle mannosyl residue was found. The transfer of the three P-EthN groups present in the GPI glycan core is likely to be carried out by three different GPI-phosphoethanolamine transferases (GPI-PETs). Here we report that 1,10-phenanthroline (PNT), a commonly used inhibitor of metalloproteases, is a novel inhibitor of GPI anchor synthesis. Addition of PNT to cells caused the accumulation of GPI anchor intermediates that are substrates for GPI-PETs, suggesting that these enzymes are the targets of PNT. ZnCl(2) blocked the effect of PNT, a known Zn chelator, and Zn itself was able to stimulate the GPI anchor synthesis, indicating that this cation is likely to be required for GPI-PET activity. PNT acutely inhibited the synthesis of GPI-anchored proteins, but the synthesis was rapidly restored once the inhibitor was washed out. Therefore, PNT will be a useful tool to study the metabolism and trafficking of GPI anchor intermediates by providing a switch to turn the pathway on and off.
authors.affiliation: Department of Pharmacology, Mayo Foundation for Medical Education and Research, Mayo Clinic Jacksonville, Jacksonville, Florida 32224, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Mann
authors.forename: D
authors.initials: D
authors.lastname: Sevlever
mesh_terms: D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000818:Animals; D016466:CHO Cells; D002614:Chelating Agents / Q000378:metabolism; D006224:Cricetinae; D004983:Ethanolamines / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008358:Mannose / Q000378:metabolism; D010618:Phenanthrolines / Q000737:chemistry*; D010739:Phospholipase D / Q000378:metabolism; D011257:Pregnancy Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D011498:Protein Precursors / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D013379:Substrate Specificity; D015032:Zinc / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D004983:Ethanolamines; D017261:Glycosylphosphatidylinositols; D010618:Phenanthrolines; D011257:Pregnancy Proteins; D011498:Protein Precursors; C005448:phosphorylethanolamine; D000469:Alkaline Phosphatase; D010739:Phospholipase D; D015032:Zinc; D008358:Mannose; C025205:1,10-phenanthroline