Component of the outer cell wall layer. Required for stability of the cell wall and for optimal growth. Required for resistance against several antifungal and cell wall-perturbing agents (By similarity). Covalently attached to the cell wall. Localizes predominantly on the surface of growing buds (By similarity). The PIR1/2/3 repeat is required for the covalent linkage to the cell wall. Covalently linked to beta-1,3-glucan of the inner cell wall layer via an alkali-sensitive ester linkage between the gamma-carboxyl group of glutamic acid, arising from Gln-74 within the PIR1/2/3 repeat, and hydroxyl groups of glucoses of beta-1,3-glucan chains. Extensively O-mannosylated. Belongs to the PIR protein family.