title: TbGPI16 is an essential component of GPI transamidase in Trypanosoma brucei.
abstract: Glycosylphosphatidylinositol (GPI) is widely used by eukaryotic cell surface proteins for membrane attachment. De novo synthesized GPI precursors are attached to proteins post-translationally by the enzyme complex, GPI transamidase. TbGPI16, a component of the trypanosome transamidase, shares similarity with human PIG-T. Here, we show that TbGPI16 is the orthologue of PIG-T and an essential component of GPI transamidase by creating a TbGPI16 knockout. TbGPI16 forms a disulfide-linked complex with TbGPI8. A cysteine to serine mutant of TbGPI16 was unable to fully restore the surface expression of GPI-anchored proteins upon transfection into the knockout cells, indicating that its disulfide linkage with TbGPI8 is important for the full transamidase activity.
authors.affiliation: Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors.forename: Yeonchul
authors.initials: Y
authors.lastname: Hong
authors.forename: Kisaburo
authors.initials: K
authors.lastname: Nagamune
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Ohishi
authors.forename: Yasu S
authors.initials: YS
authors.lastname: Morita
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ashida
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Maeda
authors.forename: Taroh
authors.initials: T
authors.lastname: Kinoshita
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D004220:Disulfides / Q000378:metabolism; D018390:Gene Targeting; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D046912:Multiprotein Complexes; D009154:Mutation; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D015800:Protozoan Proteins / Q000378:metabolism; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics
chemical_list: D004220:Disulfides; D008562:Membrane Glycoproteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; D015800:Protozoan Proteins; C053277:procyclic acidic repetitive protein, Trypanosoma; D000217:Acyltransferases; C081007:COOH-terminal signal transamidase