@article {686,
	title = {Identification of a second catalytically active trans-sialidase in Trypanosoma brucei.},
	journal = {Biochem Biophys Res Commun},
	volume = {415},
	year = {2011},
	month = {2011 Nov 18},
	pages = {421-5},
	abstract = {The procyclic stage of Trypanosoma brucei is covered by glycosylphosphatidylinositol (GPI)-anchored surface proteins called procyclins. The procyclin GPI anchor contains a side chain of N-acetyllactosamine repeats terminated by sialic acids. Sialic acid modification is mediated by trans-sialidases expressed on the parasite{\textquoteright}s cell surface. Previous studies suggested the presence of more than one active trans-sialidases, but only one has so far been reported. Here we cloned and examined enzyme activities of four additional trans-sialidase homologs, and show that one of them, Tb927.8.7350, encodes another active trans-sialidase, designated as TbSA C2. In an in vitro assay, TbSA C2 utilized α2-3 sialyllactose as a donor, and produced an α2-3-sialylated product, suggesting that it is an α2-3 trans-sialidase. We suggest that TbSA C2 plays a role in the sialic acid modification of the trypanosome cell surface.},
	keywords = {Amino Sugars, Catalysis, Cell Membrane, Cloning, Molecular, Glycoproteins, Glycosylphosphatidylinositols, Mutation, N-Acetylneuraminic Acid, Neuraminidase, Trypanosoma brucei brucei},
	issn = {1090-2104},
	doi = {10.1016/j.bbrc.2011.10.085},
	author = {Nakatani, Fumiki and Morita, Yasu S and Ashida, Hisashi and Nagamune, Kisaburo and Maeda, Yusuke and Kinoshita, Taroh}
}
@article {693,
	title = {Removal or maintenance of inositol-linked acyl chain in glycosylphosphatidylinositol is critical in trypanosome life cycle.},
	journal = {J Biol Chem},
	volume = {281},
	year = {2006},
	month = {2006 Apr 28},
	pages = {11595-602},
	abstract = {The protozoan parasite Trypanosoma brucei is coated by glycosylphosphatidylinositol (GPI)-anchored proteins. During GPI biosynthesis, inositol in phosphatidylinositol becomes acylated. Inositol is deacylated prior to attachment to variant surface glycoproteins in the bloodstream form, whereas it remains acylated in procyclins in the procyclic form. We have cloned a T. brucei GPI inositol deacylase (GPIdeAc2). In accordance with the acylation/deacylation profile, the level of GPIdeAc2 mRNA was 6-fold higher in the bloodstream form than in the procyclic form. Knockdown of GPIdeAc2 in the bloodstream form caused accumulation of an inositol-acylated GPI, a decreased VSG expression on the cell surface and slower growth, indicating that inositol-deacylation is essential for the growth of the bloodstream form. Overexpression of GPIdeAc2 in the procyclic form caused an accumulation of GPI biosynthetic intermediates lacking inositol-linked acyl chain and decreased cell surface procyclins because of release into the culture medium, indicating that overexpression of GPIdeAc2 is deleterious to the surface coat of the procyclic form. Therefore, the GPI inositol deacylase activity must be tightly regulated in trypanosome life cycle.},
	keywords = {Acylation, Animals, Cloning, Molecular, Glycosylphosphatidylinositols, Inositol, Life Cycle Stages, Membrane Glycoproteins, Phosphoric Monoester Hydrolases, Protozoan Proteins, RNA, Messenger, Trypanosoma brucei brucei},
	issn = {0021-9258},
	doi = {10.1074/jbc.M513061200},
	author = {Hong, Yeonchul and Nagamune, Kisaburo and Morita, Yasu S and Nakatani, Fumiki and Ashida, Hisashi and Maeda, Yusuke and Kinoshita, Taroh}
}
@article {695,
	title = {TbGPI16 is an essential component of GPI transamidase in Trypanosoma brucei.},
	journal = {FEBS Lett},
	volume = {580},
	year = {2006},
	month = {2006 Jan 23},
	pages = {603-6},
	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.},
	keywords = {Acyltransferases, Animals, Disulfides, Gene Targeting, Humans, Membrane Glycoproteins, Multiprotein Complexes, Mutation, Protein Subunits, Protozoan Proteins, Trypanosoma brucei brucei},
	issn = {0014-5793},
	doi = {10.1016/j.febslet.2005.12.075},
	author = {Hong, Yeonchul and Nagamune, Kisaburo and Ohishi, Kazuhito and Morita, Yasu S and Ashida, Hisashi and Maeda, Yusuke and Kinoshita, Taroh}
}
@article {698,
	title = {PIG-V involved in transferring the second mannose in glycosylphosphatidylinositol.},
	journal = {J Biol Chem},
	volume = {280},
	year = {2005},
	month = {2005 Mar 11},
	pages = {9489-97},
	abstract = {Glycosylphosphatidylinositol (GPI) is a glycolipid that anchors many proteins to the eukaryotic cell surface. The biosynthetic pathway of GPI is mediated by sequential additions of sugars and other components to phosphatidylinositol. Four mannoses in the GPI are transferred from dolichol-phosphate-mannose (Dol-P-Man) and are linked through different glycosidic linkages. Therefore, four Dol-P-Man-dependent mannosyltransferases, GPI-MT-I, -MT-II, -MT-III, and -MT-IV for the first, second, third, and fourth mannoses, respectively, are required for generation of GPI. GPI-MT-I (PIG-M), GPI-MT-III (PIG-B), and GPI-MT-IV (SMP3) were previously reported, but GPI-MT-II remains to be identified. Here we report the cloning of PIG-V involved in transferring the second mannose in the GPI anchor. Human PIG-V encodes a 493-amino acid, endoplasmic reticulum (ER) resident protein with eight putative transmembrane regions. Saccharomyces cerevisiae protein encoded in open reading frame YBR004c, which we termed GPI18, has 25\% amino acid identity to human PIG-V. Viability of the yeast gpi18 deletion mutant was restored by human PIG-V cDNA. PIG-V has two functionally important conserved regions facing the ER lumen. Taken together, we suggest that PIG-V is the second mannosyltransferase in GPI anchor biosynthesis.},
	keywords = {Amino Acid Sequence, Animals, Cell Line, Tumor, CHO Cells, Cloning, Molecular, Conserved Sequence, Cricetinae, DNA Primers, Glioma, Glycosylphosphatidylinositols, Humans, Mannose, Mannosyltransferases, Molecular Sequence Data, Open Reading Frames, Rats, Restriction Mapping, Saccharomyces cerevisiae, Sequence Alignment, Sequence Homology, Amino Acid},
	issn = {0021-9258},
	doi = {10.1074/jbc.M413867200},
	author = {Kang, Ji Young and Hong, Yeongjin and Ashida, Hisashi and Shishioh, Nobue and Murakami, Yoshiko and Morita, Yasu S and Maeda, Yusuke and Kinoshita, Taroh}
}
