Zinc transporter protein explained

Zinc transporter proteins (Zrt), or simply zinc transporters, are membrane transport proteins of the solute carrier family which control the membrane transport of zinc and regulate its intracellular and cytoplasmic concentrations.^[1] They include two major groups: (1) the zinc transporter (ZnT) or solute carrier 30 (SLC30) family, which controls the efflux of zinc from the cytoplasm out of the cell and from the cytoplasm into vesicles; and (2) the zinc importer, Zrt- and Irt-like protein (ZIP), or solute carrier 39A (SLC39A) family, which controls the influx of zinc into the cytoplasm from outside the cell and from vesicles.

At least one zinc transporter, ZIP9, is also a G protein-coupled receptor and membrane androgen receptor.^[2]

Families

ZnT (SLC30)

Members: ZnT1, ZnT2, ZnT3, ZnT4, ZnT5, ZnT6, ZnT7, ZnT8, ZnT9, ZnT10

Bacterial members of the family are known to increase tolerance to high salt concentrations.

ZntB Zinc Transporter Protein

Unlike some other zinc transporter proteins, the mechanism of how Zn²⁺ is transported via ZntB is not well understood. However, scientists have been able to speculate that the transport of Zn²⁺ is related to pH gradient and the electrostatics of the protein membrane.^{[3] [4]}

ZIP (SLC39)

ZIP1, ZIP2, ZIP3, ZIP4, ZIP5, ZIP6, ZIP7 (Catsup), ZIP8, ZIP9, ZIP10, ZIP11, ZIP12, ZIP13, ZIP14

The structure of a bacterial ZIP protein has been resolved.^[5]

Notes and References

1. Hara T, Takeda TA, Takagishi T, Fukue K, Kambe T, Fukada T . Physiological roles of zinc transporters: molecular and genetic importance in zinc homeostasis . The Journal of Physiological Sciences . 67 . 2 . 283–301 . March 2017 . 28130681 . 10.1007/s12576-017-0521-4 . free . 10717645 .
2. Thomas P, Converse A, Berg HA . ZIP9, a novel membrane androgen receptor and zinc transporter protein . General and Comparative Endocrinology . 257 . 130–136 . February 2018 . 28479083 . 10.1016/j.ygcen.2017.04.016 .
3. Gati C, Stetsenko A, Slotboom DJ, Scheres SH, Guskov A . The structural basis of proton driven zinc transport by ZntB . En . Nature Communications . 8 . 1 . 1313 . November 2017 . 29101379 . 5670123 . 10.1038/s41467-017-01483-7 . Sjors Scheres . 2017NatCo...8.1313G .
4. Tan K, Sather A, Robertson JL, Moy S, Roux B, Joachimiak A . Structure and electrostatic property of cytoplasmic domain of ZntB transporter . Protein Science . 18 . 10 . 2043–52 . October 2009 . 19653298 . 2786968 . 10.1002/pro.215 .
5. Zhang T, Liu J, Fellner M, Zhang C, Sui D, Hu J . Crystal structures of a ZIP zinc transporter reveal a binuclear metal center in the transport pathway . Science Advances . 3 . 8 . e1700344 . August 2017 . 28875161 . 5573306 . 10.1126/sciadv.1700344 . free . 2017SciA....3E0344Z .