A cysteine-rich extracellular protein containing a PA14 domain mediates quorum sensing in Dictyostelium discoideum.

Much remains to be understood about quorum-sensing factors that allow cells to sense their local density. Dictyostelium discoideum is a simple eukaryote that grows as single-celled amoebae and switches to multicellular development when food becomes limited. As the growing cells reach a high density, they begin expressing discoidin genes.