TbGPI16 is an essential component of GPI transamidase in Trypanosoma brucei.
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.
Hong
Yeonchul
Y
Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Nagamune
Kisaburo
K
Ohishi
Kazuhito
K
Morita
Yasu S
YS
Ashida
Hisashi
H
Maeda
Yusuke
Y
Kinoshita
Taroh
T
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
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