The large intracellular loop of hZIP4 is an intrinsically disordered zinc binding domain.

Abstract

The human (h) ZIP4 transporter is a plasma membrane protein which functions to increase the cytosolic concentration of zinc. hZIP4 transports zinc into intestinal cells and therefore has a central role in the absorption of dietary zinc. hZIP4 has eight transmembrane domains and encodes a large intracellular loop between transmembrane domains III and IV, M3M4. Previously, it has been postulated that this domain regulates hZIP4 levels in the plasma membrane in a zinc-dependent manner. The objective of this research was to examine the zinc binding properties of the large intracellular loop of hZIP4. Therefore, we have recombinantly expressed and purified M3M4 and showed that this domain binds t..