High-level expression of the Toxoplasma gondii STT3 gene is required for suppression of the yeast STT3 gene mutation.
N-linked glycosylation is the most frequent modification of secretory proteins. The central reaction of this process in eukaryotic cells is catalyzed by the hetero-oligomeric protein complex oligosaccharyltransferase (OST). The gene STT3 gene encodes a protein, which is the most conserved among the components of the OST. In this report, we describe the isolation and functional characterization of a STT3 homologue from Toxoplasma gondii. The topology of the TgStt3p is similar to that of the yeast Stt3p with 47% identity. We demonstrate that high level expression of the homologues gene is required to completely suppress the defect caused by a stt3 mutation in yeast, suggesting that homologous Stt3 proteins can serve analogous functions in distantly related eukaryotic cells regardless of their degree of conservation.
Shams-Eldin
Hosam
H
Institute for Virology, Medical Center for Hygiene and Medical Microbiology, Philipps University Marburg, Robert Koch Strasse 17, DE-35037 Marburg, Germany.
Blaschke
Thomas
T
Anhlan
Darisuren
D
Niehus
Sebastian
S
Müller
Jan
J
Azzouz
Nahid
N
Schwarz
Ralph T
RT
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016384:Consensus Sequence; D017124:Conserved Sequence; D017931:DNA Primers; D004926:Escherichia coli / Q000235:genetics; D006602:Hexosyltransferases / Q000235:genetics*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D021122:Protein Subunits / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D014122:Toxoplasma / Q000235:genetics*
D017931:DNA Primers; D008565:Membrane Proteins; D021122:Protein Subunits; D015800:Protozoan Proteins; D029701:Saccharomyces cerevisiae Proteins; D006602:Hexosyltransferases; C096554:STT3 protein, S cerevisiae; C025620:dolichyl-diphosphooligosaccharide - protein glycotransferase