Involved in a late stage of cell wall 1,6-beta-glucan synthesis and assembly. Has a structural, rather than enzymic, function within cell wall 1,6-beta-glucan assembly and architecture, possibly by being involved in covalently cross-linking 1,6-beta-glucans to other cell wall components such as 1,3-beta-glucan, chitin and certain mannoproteins. Acts as the plasma membrane receptor for the yeast K1 viral toxin. Identified as GPI-anchored plasma membrane protein (GPI-PMP) as well as component of the cell wall. Concentrated at the surface of mother cells. Extensively modified; probably through addition of O-linked mannose residues. 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 (By similarity). Present with 623 molecules/cell in log phase SD medium. Belongs to the KRE1 family.