Functions of ZnT transporters localized to the early secretory pathway

摘要

Secretory and membrane-bound zinc enzymes have multiple important physiological functions. Hence, the activation process of these enzymes is thought to require spatially and temporally well-organized steps of zinc transport, trafficking, transfer, and coordination. However, the molecular mechanisms involved in this activation remain largely unexplored when compared with those of other metal enzymes. Further investigation is essential to understanding how zinc metabolism is sophisticatedly controlled, thereby contributing to greater understanding of zinc-related biology in contexts from physiology to diseases. In this review, current knowledge on the crucial roles of the ZnT family of zinc transporters, which are localized to the early secretory pathway, is briefly reviewed from the perspective of these transporters' involvement in the activation process of secretory and membrane-bound zinc enzymes. The roles of those ZnT transporters in the maintenance of secretory pathway homeostasis are also reviewed, emphasizing the molecular aspects.