MATalpha-specific protein that interferes with a-factor, the pheromone secreted by MATa cells (PubMed:24121774). Contributes to mating efficiency (PubMed:24121774). Acts to bind and sequester a-factor rather than to degrade it, and promotes the efficient mating of MATalpha cells by keeping the a-factor concentration at the plasma membrane within the narrow range needed for accurate pheromone gradient detection (Probable). Expression is up-regulated by the MCM1 alpha cell-type-specific transcription factor. 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). Belongs to the SRP1/TIP1 family.