Zinc, an essential element required for cell proliferation and differentiation, plays a role in a diverse array of cellular functions, including acting as a cofactor for numerous enzymes and transcription factors and as a neuroregulator. ZnT proteins also belong to the cation diffusion facilitator (CDF) transporter family of metal ion transporters. ZnT-9, also known as HUEL (human embryonic lung protein), GAC63 (GRIP1-associated coactivator 1) or SLC30 member 9, displays ubiquitous expression in fetal and adult tissues as well as cancer cell lines. ZnT-9 localizes to the cytoplasm and is translocated to the nucleus during S phase. ZnT-9 has the lowest homology with the other zinc transporters and may function as a DNA-binding protein.