Cell wall protein which mediates cell-cell and cell-substrate adhesion. Required for biofilm formation and plays a role in virulence. Expressed in white cells. Transcription is regulated by the transcription factor EFG1 and up-regulated by alpha-pheromone, by host serum, in biofilms, and in high iron conditions. Repressed by BCR1 in a/a biofilms. The N-terminal domain mediates haploid invasive growth and yeast cell-cell adhesion. The regions containing tandem repeats are required to project the N-terminal region into the extracellular environment and to mediate adhesion to polystyrene and to host cells. In allele CaO19.8979, the N-terminal tandem repeat region is expended and contains up to 90 repeats and the C-terminal tandem repeat region has one more repeat. 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. Belongs to the PGA18 family.