Component of the cell wall. May play a role in the formation of a tightly packed outer mannan layer, which protects the inner glucan. Covalently-linked GPI-modified cell wall protein (GPI-CWP). Extensively O-glycosylated; glycans consist probably of single mannose residues. N-glycosylated. 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 158000 molecules/cell in log phase SD medium. To yeast protein YDR134C.