Euplotes pheromones

Species of Euplotes secrete protein signals (pheromones) in relation with their mating-type mechanisms of self-nonself recognition. Significant numbers of these pheromones have been characterized to varied extents of structural complexity in E. raikovi, E. nobilii, and E. octocarinatus. In every case, they form species-specific families of structurally homologous, cysteine-rich proteins. In E. raikovi, these proteins have been shown to share a common architecture based on a three-helix bundle, that permits them to bind to cells in competition with one another and elicit varied, context-dependent responses.