RLI family systems are found in eukaryotes and archaea. These systems are comprised of a protein with an ABC2 organization. The mammalian RNase L inhibitor or RLI modulates the activity of RNase L, an enzyme that participate in interferon action and could possibly play a more general physiological role in the regulation of RNA stability ( Pubmed : 10866653 ) . The absence of known RNase L homologues in eukaryotes other than mammals suggest a more general role for RLI proteins ( Pubmed : 15351708 ) . Proteins homologous to RLI have also been identified in lower eukaryotes and in archaea but their function has not been investigated yet.