Titre
Purification, biosynthesis and cellular localization of a major 125-kDa glycophosphatidylinositol-anchored membrane glycoprotein of Saccharomyces cerevisiae.
Type
article
Institution
UNIL/CHUV/Unisanté + institutions partenaires
Périodique
European Journal of Biochemistry / Febs
Auteur(s)
Fankhauser, C.
Auteure/Auteur
Conzelmann, A.
Auteure/Auteur
Liens vers les unités
ISSN
0014-2956[print], 0014-2956[linking]
Statut éditorial
Publié
Date de publication
1991-01
Volume
195
Numéro
2
Première page
439
Dernière page/numéro d’article
448
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Publication Status: ppublish
Résumé
The yeast Saccharomyces cerevisiae has been shown to contain a major 125-kDa membrane glycoprotein which is anchored in the lipid bilayer by a glycophosphatidylinositol anchor. This protein was purified to near homogeneity and was used to raise a rabbit antibody. Biosynthesis of the 125-kDa protein was studied by immunoprecipitation of 35SO4-labeled material from wild-type cells or a secretion mutant (sec18) in which the vesicular traffic from the endoplasmic reticulum (ER) to the Golgi is blocked. The 125-kDa protein is first made in the ER as a 105-kDa precursor which already contains a glycophosphatidylinositol anchor and which is slowly transformed into the 125-kDa form upon chase (t1/2 approximately 10-15 min). The 105-kDa precursor can be reduced to an 83-kDa form by the enzymatic removal of N-glycans. The removal of N-glycans from the mature 125-kDa protein yields a 95-kDa species. Thus, removal of the N-glycans does not reduce the ER and mature forms to the same molecular mass, indicating that not only elongation of N-glycans but also another post-translational modification takes place during maturation. Selective tagging of surface proteins by treatment of 35SO4-labeled cells with trinitrobenzene sulfonic acid at 0 C followed by immunoprecipitation of the tagged proteins shows that the 125-kDa protein, but not the 105-kDa precursor, becomes transported to the cell surface. This tagging of cells after various lengths of chase also shows that the surface appearance of the protein is biphasic with about one half of the mature 125-kDa protein remaining intracellular for over 2 h. Glycosylation and/or glycophosphatidylinositol anchor addition is important for the stability of the 125-kDa protein since the protein remains undetectable in sec53, a temperature-sensitive mutant which does not make GDP-mannose at 37 C and does not add glycophosphatidylinositol anchors at 37 degrees C.
Sujets
PID Serval
serval:BIB_502E5193140C
PMID
Open Access
Oui
Date de création
2008-01-24T14:29:29.184Z
Date de création dans IRIS
2025-05-20T14:58:42Z