Open AccessSite‐specific O ‐glycosylation of human granulocyte/macrophage colony‐stimulating factor secreted by yeast and animal cells
Author(s) -
ERNST Joachim F.,
MERMOD JeanJacques,
RICHMAN Larry H.
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb16596.x
Subject(s) - yeast , glycosylation , saccharomyces cerevisiae , glycosyl , biochemistry , mutant , chemistry , biology , gene
To compare the site specificity of O ‐glycosylation in lower and higher eukaryotes, we expressed human granulocyte/macrophage colony‐stimulating factor (hGM‐CSF) in the yeast Saccharomyces cerevisiae and in COS‐1 cells. Analyses of specific hGM‐CSF mutants secreted by yeast led to the conclusion that efficient O ‐glycosylation in yeast requires residues S9 and T10. However, only S9 is used as an attachment point for an extended O ‐glycosyl chain in a 15.5‐kDa hGM‐CSF form. A 14.5‐kDa hGM‐CSF form, secreted by yeast, appears substituted by single mannosyl residues at both positions S9 and T10, indicating that O ‐glycosylation at T10 inhibits extension of the O ‐glycosyl chain attached to S9. As in yeast cells, the addition of O ‐glycosyl chains to hGM‐CSF secreted by COS‐1 cells requires the presence of S9 and T10 residues. These results demonstrate that, inspite of different biosynthetic routes, the selection of O ‐glycosylation sites is similar between lower and higher eukaryotes.