This family consists of several mating pheromone proteins from Euplotes octocarinatus. Cells of the ten mating types of the ciliate Euplotes octocarinatus communicate by pheromones before they enter conjugation. The pheromones induce homotypic pairing when applied to mating types that do not secrete the same pheromone(s). Heterotypic pairs (i.e., those between cells of different mating types) are formed only when both mating types in a mixture secrete a pheromone that the other does not. The genetics of mating types is based on four codominant mating type alleles, each allele determining production of a different pheromone. The pheromones not only induce pair formation but also attract cells [1].

1: Pheromones of the ciliate Euplotes octocarinatus not only induce conjugation but also function as chemoattractants. Kuhlmann HW, Brunen-Nieweler C, Heckmann K; J Exp Zool 1997;277:38-48. PMID:9018841