Acts as a quorum sensing protein regulating discoidin gene expression during growth and development. D.discoideum is a 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. The ability of psiF/dicA to induce discoidin gene expression when present in conditioned medium, suggests that it allow cells to sense their local density. Forms a complex with dicB. Expressed in vegetative and developing cells. According to PubMed:15947191, it is secreted in the conditioned medium. However, prediction tools clearly predict a transmembrane domain. In some conditions, it may be cleaved and secreted in the conditioned medium, which would explain the discrepancy. Belongs to the prespore-cell-inducing factor family.