Enzymes
UniProtKB help_outline | 1,065 proteins |
Reaction participants Show >> << Hide
- Name help_outline Cd2+ Identifier CHEBI:48775 (CAS: 22537-48-0) help_outline Charge 2 Formula Cd InChIKeyhelp_outline WLZRMCYVCSSEQC-UHFFFAOYSA-N SMILEShelp_outline [Cd++] 2D coordinates Mol file for the small molecule Search links Involved in 5 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline hydrogencarbonate Identifier CHEBI:17544 (Beilstein: 3903504; CAS: 71-52-3) help_outline Charge -1 Formula CHO3 InChIKeyhelp_outline BVKZGUZCCUSVTD-UHFFFAOYSA-M SMILEShelp_outline OC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 58 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:62256 | RHEA:62257 | RHEA:62258 | RHEA:62259 | |
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Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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ZIP8, member of the solute-carrier-39 (SLC39) metal-transporter family: characterization of transporter properties.
He L., Girijashanker K., Dalton T.P., Reed J., Li H., Soleimani M., Nebert D.W.
Cadmium is a dangerous metal distributed widely in the environment. Members of our laboratory recently identified the ZIP8 transporter protein, encoded by the mouse Slc39a8 gene, to be responsible for genetic differences in response to cadmium damage of the testis. Stable retroviral infection of t ... >> More
Cadmium is a dangerous metal distributed widely in the environment. Members of our laboratory recently identified the ZIP8 transporter protein, encoded by the mouse Slc39a8 gene, to be responsible for genetic differences in response to cadmium damage of the testis. Stable retroviral infection of the ZIP8 cDNA in mouse fetal fibroblast cultures (rvZIP8 cells) leads to as much as a 10-fold increase in the rate of intracellular cadmium influx and accumulation. In the present study, we showed that cadmium uptake operated maximally at pH 7.5 and a temperature of 37 degrees C and was inhibited by cyanide. Of more than a dozen cations tested, manganese(II) was the best competitive cation for cadmium uptake. The Km for Cd2+ uptake was 0.62 microM, and the Km for Mn2+ uptake was 2.2 microM; thus, manganese is probably the physiological substrate for ZIP8. Cadmium uptake was independent of sodium, potassium or chloride ions, but strongly dependent on the presence of bicarbonate. By Western blot analysis of rvZIP8 cells, we showed that ZIP8 protein was glycosylated. Using Z-stack confocal microscopy in Madin-Darby canine kidney polarized epithelial cells, we found that ZIP8 was localized on the apical side-implying an important role for manganese or cadmium uptake and disposition. It is likely that ZIP8 is a Mn2+/HCO3- symporter, that a HCO3-gradient across the plasma membrane acts as the driving force for manganese uptake, and that cadmium is a rogue hitchhiker displacing manganese to cause cadmium-associated disease. << Less
Mol. Pharmacol. 70:171-180(2006) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.
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Cd2+ versus Zn2+ uptake by the ZIP8 HCO3--dependent symporter: kinetics, electrogenicity and trafficking.
Liu Z., Li H., Soleimani M., Girijashanker K., Reed J.M., He L., Dalton T.P., Nebert D.W.
The mouse Slc39a8 gene encodes the ZIP8 transporter, which has been shown to be a divalent cation/HCO3-symporter. Using ZIP8 cRNA-injected Xenopus oocyte cultures, we show herein that: [a] ZIP8-mediated cadmium (Cd(2+)) and zinc (Zn(2+)) uptake have V(max) values of 1.8+/-0.08 and 1.0+/-0.08 pmol/ ... >> More
The mouse Slc39a8 gene encodes the ZIP8 transporter, which has been shown to be a divalent cation/HCO3-symporter. Using ZIP8 cRNA-injected Xenopus oocyte cultures, we show herein that: [a] ZIP8-mediated cadmium (Cd(2+)) and zinc (Zn(2+)) uptake have V(max) values of 1.8+/-0.08 and 1.0+/-0.08 pmol/oocyte/h, and K(m) values of 0.48+/-0.08 and 0.26+/-0.09 microM, respectively; [b] ZIP8-mediated Cd(2+) uptake is most inhibited by Zn(2+), second-best inhibited by Cu(2+), Pb(2+) and Hg(2+), and not inhibited by Mn(2+) or Fe(2+); and [c] electrogenicity studies demonstrate an influx of two HCO3-anions per one Cd(2+) (or one Zn(2+)) cation, i.e. electroneutral complexes. Using Madin-Darby canine kidney (MDCK) polarized epithelial cells retrovirally infected with ZIP8 cDNA and tagged with hemagglutinin at the C-terminus, we show that-similar to ZIP4-the ZIP8 eight-transmembrane protein is largely internalized during Zn(2+) homeostasis, but moves predominantly to the cell surface membrane (trafficking) under conditions of Zn(2+) depletion. << Less
Biochem. Biophys. Res. Commun. 365:814-820(2008) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
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Zip14 is a complex broad-scope metal-ion transporter whose functional properties support roles in the cellular uptake of zinc and nontransferrin-bound iron.
Pinilla-Tenas J.J., Sparkman B.K., Shawki A., Illing A.C., Mitchell C.J., Zhao N., Liuzzi J.P., Cousins R.J., Knutson M.D., Mackenzie B.
Recent studies have shown that overexpression of the transmembrane protein Zrt- and Irt-like protein 14 (Zip14) stimulates the cellular uptake of zinc and nontransferrin-bound iron (NTBI). Here, we directly tested the hypothesis that Zip14 transports free zinc, iron, and other metal ions by using ... >> More
Recent studies have shown that overexpression of the transmembrane protein Zrt- and Irt-like protein 14 (Zip14) stimulates the cellular uptake of zinc and nontransferrin-bound iron (NTBI). Here, we directly tested the hypothesis that Zip14 transports free zinc, iron, and other metal ions by using the Xenopus laevis oocyte heterologous expression system, and use of this approach also allowed us to characterize the functional properties of Zip14. Expression of mouse Zip14 in RNA-injected oocytes stimulated the uptake of (55)Fe in the presence of l-ascorbate but not nitrilotriacetic acid, indicating that Zip14 is an iron transporter specific for ferrous ion (Fe(2+)) over ferric ion (Fe(3+)). Zip14-mediated (55)Fe(2+) uptake was saturable (K(0.5) ≈ 2 μM), temperature-dependent (apparent activation energy, E(a) = 15 kcal/mol), pH-sensitive, Ca(2+)-dependent, and inhibited by Co(2+), Mn(2+), and Zn(2+). HCO(3)(-) stimulated (55)Fe(2+) transport. These properties are in close agreement with those of NTBI uptake in the perfused rat liver and in isolated hepatocytes reported in the literature. Zip14 also mediated the uptake of (109)Cd(2+), (54)Mn(2+), and (65)Zn(2+) but not (64)Cu (I or II). (65)Zn(2+) uptake also was saturable (K(0.5) ≈ 2 μM) but, notably, the metal-ion inhibition profile and Ca(2+) dependence of Zn(2+) transport differed from those of Fe(2+) transport, and we propose a model to account for these observations. Our data reveal that Zip14 is a complex, broad-scope metal-ion transporter. Whereas zinc appears to be a preferred substrate under normal conditions, we found that Zip14 is capable of mediating cellular uptake of NTBI characteristic of iron-overload conditions. << Less
Am. J. Physiol. 301:C862-C871(2011) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.
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ZIP8 is an iron and zinc transporter whose cell-surface expression is up-regulated by cellular iron loading.
Wang C.Y., Jenkitkasemwong S., Duarte S., Sparkman B.K., Shawki A., Mackenzie B., Knutson M.D.
ZIP8 (SLC39A8) belongs to the ZIP family of metal-ion transporters. Among the ZIP proteins, ZIP8 is most closely related to ZIP14, which can transport iron, zinc, manganese, and cadmium. Here we investigated the iron transport ability of ZIP8, its subcellular localization, pH dependence, and regul ... >> More
ZIP8 (SLC39A8) belongs to the ZIP family of metal-ion transporters. Among the ZIP proteins, ZIP8 is most closely related to ZIP14, which can transport iron, zinc, manganese, and cadmium. Here we investigated the iron transport ability of ZIP8, its subcellular localization, pH dependence, and regulation by iron. Transfection of HEK 293T cells with ZIP8 cDNA enhanced the uptake of (59)Fe and (65)Zn by 200 and 40%, respectively, compared with controls. Excess iron inhibited the uptake of zinc and vice versa. In RNA-injected Xenopus oocytes, ZIP8-mediated (55)Fe(2+) transport was saturable (K(0.5) of ∼0.7 μm) and inhibited by zinc. ZIP8 also mediated the uptake of (109)Cd(2+), (57)Co(2+), (65)Zn(2+) > (54)Mn(2+), but not (64)Cu (I or II). By using immunofluorescence analysis, we found that ZIP8 expressed in HEK 293T cells localized to the plasma membrane and partially in early endosomes. Iron loading increased total and cell-surface levels of ZIP8 in H4IIE rat hepatoma cells. We also determined by using site-directed mutagenesis that asparagine residues 40, 88, and 96 of rat ZIP8 are glycosylated and that N-glycosylation is not required for iron or zinc transport. Analysis of 20 different human tissues revealed abundant ZIP8 expression in lung and placenta and showed that its expression profile differs markedly from ZIP14, suggesting nonredundant functions. Suppression of endogenous ZIP8 expression in BeWo cells, a placental cell line, reduced iron uptake by ∼40%, suggesting that ZIP8 participates in placental iron transport. Collectively, these data identify ZIP8 as an iron transport protein that may function in iron metabolism. << Less
J. Biol. Chem. 287:34032-34043(2012) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.