AZ is likely to have more general functions than control of ODC destruction. For example, it downregulates polyamine uptake, and its forced expression slows cells growth, an effect not fully prevented by providing exog-enous polyamines. The control and functions of these two AZ forms remains to be determined. Trypanosoma brucei , the parasite responsible for Afican sleeping sickness, has an ODC structurally and enzymatically very like that of mammals, but it is stable, perhaps accounting for the curative effect of ODC inhibitors in late-stage disease. Even when both rodent ODC and AZ are expressed in the parasite, the former is stable, implying that the trypanosome proteasome itself has different substrate recognition properties from that of mammals.
Experiments are underway to clone subunits of the proteasome of the parasite.
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