Zinc is an essential nutrient for all organisms because of the many important roles this metal plays.
Movement of zinc into and out of cells and subcellular organelles is mediated by zinc transporter proteins.
In many organisms, zinc uptake is mediated by members of the ZIP family of metal ion transporters.
In mammals, the Zip1, Zip2, ZIP4, Zip4, Zip5, LIV-1 (Zip6), KE4 (Zip7), and BIGM103 (Zip8) proteins have been implicated in zinc uptake in a variety of cell and tissue types.
Zip4 (SLC39A4) belongs to the LZT subfamily.
There are two hZIP4 isoforms, which only differ in their amino and carboxy termini.
The largest isoform encodes a 647aa protein with an N-terminal signal peptide, whereas the shorter isoform has only 626aa.