A constitutive role for GPI anchors in Saccharomyces cerevisiae: cell wall targeting.
GPI anchors are widely represented among organisms and have several cellular functions. It has been proposed that in yeast there are two groups of GPI proteins: plasma membrane-resident proteins, such as Gas1p or Yap3p, and cell wall-targeted proteins, such as Tir1p or alpha-agglutinin. A model has been proposed for the plasma membrane retention of proteins from the first group because of a dibasic motif located just upstream of the GPI-anchoring signal. The results we report here are not in agreement with such a model as we show that constructs containing the C-terminal parts of Gas1p and Yap3p are also targeted to the cell wall. We also detect the genuine Gas1p after cell wall treatment with Quantazyme or Glucanex glycanases. In addition, we show that the GPI-anchoring signal from the human placental alkaline phosphatase (PLAP) is not compatible with the yeast machinery unless the human transamidase hGpi8p is co-expressed. In this condition, this human signal is able to target a protein to the cell wall. Moreover, TIR1 proved to be a multicopy suppressor of Deltagas1 mutation. The present findings suggest a constitutive role for GPI anchors in yeast: the cell wall targeting of proteins.
De Sampaïo
G
G
Laboratoire de Physiologie Moléculaire et Cellulaire, IBGC, Centre National de la Recherche Scientifique, 1 rue Camille Saint-Saëns, 33077 Bordeaux cedex, France.
Bourdineaud
J P
JP
Lauquin
G J
GJ
D000469:Alkaline Phosphatase / Q000378:metabolism; D000595:Amino Acid Sequence; D019881:Aminoacyltransferases / Q000235:genetics / Q000378:metabolism; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics; D010920:Placenta / Q000201:enzymology; D010957:Plasmids / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D028901:alpha Karyopherins; D000519:alpha-Galactosidase / Q000378:metabolism
D015815:Cell Adhesion Molecules; D005656:Fungal Proteins; C066709:GAS1 protein, S cerevisiae; D017261:Glycosylphosphatidylinositols; D008562:Membrane Glycoproteins; D009687:Nuclear Proteins; C491190:PIGK protein, human; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D028901:alpha Karyopherins; D019881:Aminoacyltransferases; C103133:GPI8 protein, S cerevisiae; C023175:transamidases; D000469:Alkaline Phosphatase; D000519:alpha-Galactosidase; C022325:aspartic proteinase A; D016282:Aspartic Acid Endopeptidases; C499266:YPS1 protein, S cerevisiae