The protein encoded by this gene belongs to the ornithine decarboxylase antizyme family; which plays a role in cell growth and proliferation by regulating intracellular polyamine levels. Expression of antizymes requires +1 ribosomal frameshifting; which is enhanced by high levels of polyamines. Antizymes in turn bind to and inhibit ornithine decarboxylase (ODC); the key enzyme in polyamine biosynthesis; thus; completing the auto-regulatory circuit. This gene encodes antizyme 1; the first member of the antizyme family; that has broad tissue distribution; and negatively regulates intracellular polyamine levels by binding to and targeting ODC for degradation; as well as inhibiting polyamine uptake. Antizyme 1 mRNA contains two potential in-frame AUGs; and studies in rat suggest that alternative use of the two translation initiation sites results in N-terminally distinct protein isoforms with different subcellular localization. Alternatively spliced transcript variants have also been noted for this gene.