In W303-derived strains, disruption of FIG2 increased agglutinability of alpha cells, but not a cells, and did not alter expression of alpha-agglutinin, binding of 125I-labeled alpha-agglutinin, or mating efficiency. Fig2p overexpression led to alpha-cell-specfic suppression of agglutinability. These results imply that Fig2p is an indirect masker of the active sites in alpha-agglutinin.