 Homologues of PIAS proteins have been found in other eukaryotes, including Zimp/dPIAS in "Drosophila melanogaster" and zfPIAS4a in zebrafish.SIZ1 and SIZ2 were two homologues identified in yeast.PIAS proteins contain each conserved domain and motif of the PIAS protein family, with a few exceptions.