TY - JOUR
T1 - ZnT-1 extrudes zinc from mammalian cells functioning as a Zn 2+/H+ exchanger
AU - Shusterman, Eden
AU - Beharier, Ofer
AU - Shiri, Levy
AU - Zarivach, Raz
AU - Etzion, Yoram
AU - Campbell, Craig R.
AU - Lee, Il Ha
AU - Okabayashi, Ken
AU - Dinudom, Anuwat
AU - Cook, David I.
AU - Katz, Amos
AU - Moran, Arie
PY - 2014/1/1
Y1 - 2014/1/1
N2 - ZnT-1 is a Cation Diffusion Facilitator (CDF) family protein, and is present throughout the phylogenetic tree from bacteria to humans. Since its original cloning in 1995, ZnT-1 has been considered to be the major Zn 2+ extruding transporter, based on its ability to protect cells against zinc toxicity. However, experimental evidence for ZnT-1 induced Zn 2+ extrusion was not convincing. In the present study, based on the 3D crystal structure of the ZnT-1 homologue, YiiP, that predicts a homodimer that utilizes the H+ electrochemical gradient to facilitate Zn 2+ efflux, we demonstrate ZnT-1 dependent Zn2+ efflux from HEK 293T cells using FluoZin-3 and Fura 2 by single cell microscope based fluorescent imaging. ZnT-1 facilitates zinc efflux in a sodium-independent, pH-driven and calcium-sensitive manner. Moreover, substitution of two amino acids in the putative zinc binding domain of ZnT-1 led to nullification of Zn2+ efflux and rendered the mutated protein incapable of protecting cells against Zn2+ toxicity. Our results demonstrate that ZnT-1 extrudes zinc from mammalian cells by functioning as a Zn2+/H + exchanger.
AB - ZnT-1 is a Cation Diffusion Facilitator (CDF) family protein, and is present throughout the phylogenetic tree from bacteria to humans. Since its original cloning in 1995, ZnT-1 has been considered to be the major Zn 2+ extruding transporter, based on its ability to protect cells against zinc toxicity. However, experimental evidence for ZnT-1 induced Zn 2+ extrusion was not convincing. In the present study, based on the 3D crystal structure of the ZnT-1 homologue, YiiP, that predicts a homodimer that utilizes the H+ electrochemical gradient to facilitate Zn 2+ efflux, we demonstrate ZnT-1 dependent Zn2+ efflux from HEK 293T cells using FluoZin-3 and Fura 2 by single cell microscope based fluorescent imaging. ZnT-1 facilitates zinc efflux in a sodium-independent, pH-driven and calcium-sensitive manner. Moreover, substitution of two amino acids in the putative zinc binding domain of ZnT-1 led to nullification of Zn2+ efflux and rendered the mutated protein incapable of protecting cells against Zn2+ toxicity. Our results demonstrate that ZnT-1 extrudes zinc from mammalian cells by functioning as a Zn2+/H + exchanger.
UR - http://www.scopus.com/inward/record.url?scp=84906535610&partnerID=8YFLogxK
U2 - https://doi.org/10.1039/c4mt00108g
DO - https://doi.org/10.1039/c4mt00108g
M3 - Article
C2 - 24951051
SN - 1756-5901
VL - 6
SP - 1656
EP - 1663
JO - Metallomics
JF - Metallomics
IS - 9
ER -