Amino acid sequence requirement for efficient incorporation of glycosylphosphatidylinositol-associated proteins into the cell wall of Saccharomyces cerevisiae

Abstract

During cell wall biogenesis in Saccharomyces cerevisiae, some glycosylphosphatidylinositol (GPI)-attached proteins are detached from GPI moieties and bound to β-1,6-glucan of the cell wall. The amino acid sequence requirement for the incorporation of GPI-attached proteins into the cell wall was studied by using reporter fusion proteins. Only the short ω-minus region composed of five amino acids, which is located upstream of the ω site for GPI attachment, determined the cellular localization of the GPI-associated proteins. Within the ω-minus region, amino acid residues at the ω-4 or -5 and ω-2 sites were important for the cell wall incorporation. Yap3p, a well characterized GPI-anchored plasma membrane aspartic protease, was localized in the cell wall when the ω-minus region was mutated to sequences containing Val or Ile at the ω-4 or -5 site and Val or Tyr at the ω-2 site.