Zinc transporter 6

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:

• Members of the SLC39 family (Zip, "Zrt- and Irt-like proteins") increase the cytoplasmic zinc level by zinc uptake.
• Members of the SLC30 family (ZnT, zinc transporter/exporter; CDF family, cation diffusion facilitator) lower intracellular zinc concentrations by transporting zinc out of the cell or into vesicular structures. So far, 15 Zips and 9 ZnTs have been detected in various human cells.

Like ZnT-5, the zinc transporter ZnT-6 mediates the transport of zinc from the cytoplasm into the trans-Golgi apparatus as well as into the vesicular compartment. While the RNA could be detected in the liver, kidney, brain and intestine, the protein was found in the brain and lung (Huang et al.2002). The expression of ZnT-7 is strongest in the liver and small intestine and shows lower levels in the kidney, spleen, heart, brain and lung.

1. Huang L et al (2002) Functional characterization of a novel mammalian zinc transporter, ZnT6. J Biol Chem 277: 26389-26395.
2. Iguchi K et al (2002) High-level expression of zinc transporter-2 in the rat lateral and dorsal prostate. J Androl 23: 819-824.
3. Inoue K et al (2002) Osteopenia and male-specific sudden cardiac death in mice lacking a zinc transporter gene, Znt5. Human Mol Genet 11: 1775-1784.
4. Kambe T et al (2004) Overview of mammalian zinc transporters. Cell Mol Life Sci 61: 49-68.
5. Michalczyk AA et al. (2002) Constitutive expression of hZnT4 zinc transporter in human breast epithelial cells. Biochem J 364: 105-113.
6. Overbeck S (2008) The regulation of zinc transporters and their influence on intracellular zinc homeostasis in leukocytes. Dissertation. Publication server of RWTH Aachen University