Zinc transporter 4 (ZnT4)

Zinc transporter 4 (ZnT4; encoded by SLC30A4) is a membrane protein belonging to the solute carrier family 30, functioning primarily as a zinc efflux transporter responsible for moving zinc ions out of the cytoplasm, either into intracellular compartments (such as the trans-Golgi network and vesicles) or possibly out of the cell. ZnT4 is essential for maintaining proper zinc homeostasis, is highly expressed in secretory cells such as those in the mammary gland, and is required for supplying zinc to zinc-dependent secretory proteins, particularly during lactation. Mutations in SLC30A4 can result in zinc transport defects contributing to inherited/acquired zinc deficiency states, including acrodermatitis enteropathica and the “lethal milk” phenotype in mice, which is characterized by severely reduced zinc content in milk and poor offspring survival. The transporter is characterized by six transmembrane domains and a histidine-rich cytoplasmic loop, features common to members of the ZnT (SLC30) family. Currently, there are no drugs directly targeting ZnT4 in clinical use. SLC30A4 participates in zinc efflux from the cytoplasm to various intracellular locations and is critical in the secretory pathway of mammary epithelial cells. Deficiencies or mutations affecting ZnT4 reduce zinc content in secreted milk, leading to zinc-deficient syndromes in neonates in animal models. ZnT4 is structurally and functionally part of the wider ZnT family of zinc transporters, which act to lower cytoplasmic zinc and support organelle-specific zinc-mediated functions.

Other names

Solute carrier family 30 member 4SLC30A4ZNT4Zinc transporter 4ZnT-4

Not established for therapeutic drugs, as there are no approved small molecules or biologics known to target ZnT4 or modulate its activity directly.