Zinc transporter 8

Intracellular zinc homeostasis is regulated by zinc-binding proteins and zinc transporters (Rink et al. 2007). The zinc transporters are encoded by two SLC ("solute linked carrier") gene families:

• SLC39 family members (Zip, "Zrt- and Irt-like proteins") increase cytoplasmic zinc levels by zinc uptake.
• Members of the SLC30 family (ZnT, zinc transporter/exporter; CDF family, "cation diffusion facilitator") decrease intracellular zinc concentration by transporting zinc out of the cell or into vesicular structures.

To date, 15 Zips and 9 ZnTs have been detected in various, human cells.

The zinc transporter 8, ZnT-8 is a pancreas-specific zinc transporter expressed in pancreatic beta cells. ZnT 8 is a transmembrane protein of the secretory vesicles of beta cells and belongs to the SLC30 family.

ZnT8 is encoded by the gene SLC30A8 (Solute carrier family 30, member 8). There is an association between ZnT8 polymorphisms and type 2 diabetes. For ZnT-8, no expression has yet been shown in peripheral blood mononuclear cells (PBMC). In pancreatic beta cells, it mediates the transport of cytoplasmic zinc into intracellular vesicles, where it is required for the maturation and storage of insulin(Chimienti et al 2005).

The antibody against the zinc transporter 8 (anti-ZnT8-Ak) is a new marker in the prognosis and diagnosis of type 1 diabetes. The detection of this antibody indicates a high risk of diabetes. ZnT8 antibodies are detected in 80% of newly diagnosed type 1 diabetics, while controls showed 2%, type 2 diabetics <3%, patients with other autoimmune diseases up to 20% ZnT8 antibodies.

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