Component of the cell wall. Major cell wall protein in stationary phase cells. Required to stabilize the cell wall in the absence of multiple GPI-anchored mannoproteins. Covalently-linked GPI-modified cell wall protein (GPI-CWP). Induced in stationary phase and under conditions of stress and starvation (at protein level). The number of the intragenic tandem repeats varies between different S.cerevisiae strains. The N-terminus is blocked. The GPI-anchor is attached to the protein in the endoplasmic reticulum and serves to target the protein to the cell surface. There, the glucosamine-inositol phospholipid moiety is cleaved off and the GPI-modified mannoprotein is covalently attached via its lipidless GPI glycan remnant to the 1,6-beta-glucan of the outer cell wall layer. Present with 1630 molecules/cell in log phase SD medium. Belongs to the SED1 family.