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a r t i c l e i n f o degradation and transport across the plasma membrane [5]. rmine. Different lay an imp activity is entrations rapidly down regulated under high polyamine amounts, ac transcriptional, translational and post-translational leve Post-translational regulation of ODC is mainly mediated action of a family of small proteins named antizymes (AZs), whose synthesis is stimulated by increased polyamine levels [10]. AZs bind and inhibit ODC and target it to proteasomal degradation without ubiquitination [11,12]. Besides, AZs inhibit extracellular polyamine uptake presumably by interacting with the polyamine transport system [13–15]. In mammals, the family of AZs is com-posed by three isoforms (AZ1-3), AZ1 being the most predominant Abbreviations: AZ, antizyme; AZBE, antizyme-binding element; AZIN, antizyme inhibitor; ERGIC, endoplasmic reticulum-Golgi intermediate compartment; ODC, ornithine decarboxylase; GDT_TS, global distance test total score; HA, hemagglu-tinin; HEK, human embryonic kidney; PAGE, polyacrylamide gel electrophoresis; RMSD, root-mean-square deviation; TGN, trans-Golgi networ