SAM (sterile alpha motif) domain of BOI-like fungal subfamily is a potential protein-protein interaction domain. Proteins of this subfamily are apparently scaffold proteins, since most contain SH3 and PH domains, which are also protein-protein interaction domains, in addition to SAM domain. BOI-like proteins participate in cell cycle regulation. In particular BOI1 and BOI2 proteins of budding yeast S.cerevisiae are involved in bud formation, and POB1 protein of fission yeast S.pombe plays a role in cell elongation and separation. Among binding partners of BOI-like fungal subfamily members are such proteins as Bem1 and Cdc42 (they are known to be involved in cell polarization and bud formation).