The evolution of proopiomelanocortin: looking for the invertebrate fingerprints.

The presence and role of the pro-opiomelanocortin (POMC) gene and encoded peptides in invertebratesare here summarized and discussed. Some of the POMC-derived peptides show a significant similarityregarding their functions, suggesting their appearance before the split of protostomian–deuterostomianlineages and their maintenance during evolution. The basic mechanisms that govern the exchange ofinformation between cells are usually well conserved, and this could have also been for POMC-derivedpeptides, that are mainly involved in fundamental functions such as immune and neuroendocrineresponses. However, the presence and functions that POMC-derived peptides exhibit in taxonomicallydistant models, are not always reflected by the expected gene homology, leaving the problem of POMCevolution in invertebrates in need of additional study.