scholarly journals The trafficking of metal ion transporters of the Zrt- and Irt-like protein family

Traffic ◽  
2018 ◽  
Vol 19 (11) ◽  
pp. 813-822 ◽  
Author(s):  
Katherine Bowers ◽  
Surjit K. S. Srai
Keyword(s):  
Metal Ion ◽  
Protein Family ◽  
Ion Transporters

Properties of the mammalian and yeast metal-ion transporters DCT1 and Smf1p expressed in Xenopus laevis oocytes

2001 ◽  
Vol 204 (6) ◽  
pp. 1053-1061 ◽  
Author(s):  
A. Sacher ◽  
A. Cohen ◽  
N. Nelson
Keyword(s):  
Xenopus Laevis ◽  
Metal Ions ◽  
Metal Ion ◽  
Divalent Cations ◽  
Ion Uptake ◽  
Xenopus Laevis Oocytes ◽  
Ion Transporters ◽  
Divalent Metal Ions ◽  
Transport Pathway ◽  
Metal Ion Uptake

Transition metals are essential for many metabolic processes, and their homeostasis is crucial for life. Metal-ion transporters play a major role in maintaining the correct concentrations of the various metal ions in living cells. Little is known about the transport mechanism of metal ions by eukaryotic cells. Some insight has been gained from studies of the mammalian transporter DCT1 and the yeast transporter Smf1p by following the uptake of various metal ions and from electrophysiological experiments using Xenopus laevis oocytes injected with RNA copies (c-RNA) of the genes for these transporters. Both transporters catalyze the proton-dependent uptake of divalent cations accompanied by a ‘slippage’ phenomenon of different monovalent cations unique to each transporter. Here, we further characterize the transport activity of DCT1 and Smf1p, their substrate specificity and their transport properties. We observed that Zn(2+) is not transported through the membrane of Xenopus laevis oocytes by either transporter, even though it inhibits the transport of the other metal ions and enables protons to ‘slip’ through the DCT1 transporter. A special construct (Smf1p-s) was made to enhance Smf1p activity in oocytes to enable electrophysiological studies of Smf1p-s-expressing cells. 54Mn(2+) uptake by Smf1p-s was measured at various holding potentials. In the absence of Na(+) and at pH 5.5, metal-ion uptake was not affected by changes in negative holding potentials. Elevating the pH of the medium to 6.5 caused metal-ion uptake to be influenced by the holding potential: ion uptake increased when the potential was lowered. Na(+) inhibited metal-ion uptake in accordance with the elevation of the holding potential. A novel clutch mechanism of ion slippage that operates via continuously variable stoichiometry between the driving-force pathway (H(+)) and the transport pathway (divalent metal ions) is proposed. The possible physiological advantages of proton slippage through DCT1 and of Na(+) slippage through Smf1p are discussed.

scholarly journals Evolutionary Descent of Prion Genes from the ZIP Family of Metal Ion Transporters

PLoS ONE ◽  
2009 ◽  
Vol 4 (9) ◽  
pp. e7208 ◽  
Author(s):  
Gerold Schmitt-Ulms ◽  
Sepehr Ehsani ◽  
Joel C. Watts ◽  
David Westaway ◽  
Holger Wille
Keyword(s):  
Metal Ion ◽  
Ion Transporters ◽  
Zip Family ◽  
Evolutionary Descent

scholarly journals Comparative Genomic Analysis of the DUF34 Protein Family Suggests Role as a Metal Ion Chaperone or Insertase

Biomolecules ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1282
Author(s):  
Colbie J. Reed ◽  
Geoffrey Hutinet ◽  
Valérie de Crécy-Lagard
Keyword(s):  
Stress Responses ◽  
Metal Ion ◽  
Ion Homeostasis ◽  
Genomic Analysis ◽  
Protein Family ◽  
Comparative Genomic ◽  
Pathogen Virulence ◽  
Metal Ion Homeostasis ◽  
Domain Of Unknown Function

Members of the DUF34 (domain of unknown function 34) family, also known as the NIF3 protein superfamily, are ubiquitous across superkingdoms. Proteins of this family have been widely annotated as “GTP cyclohydrolase I type 2” through electronic propagation based on one study. Here, the annotation status of this protein family was examined through a comprehensive literature review and integrative bioinformatic analyses that revealed varied pleiotropic associations and phenotypes. This analysis combined with functional complementation studies strongly challenges the current annotation and suggests that DUF34 family members may serve as metal ion insertases, chaperones, or metallocofactor maturases. This general molecular function could explain how DUF34 subgroups participate in highly diversified pathways such as cell differentiation, metal ion homeostasis, pathogen virulence, redox, and universal stress responses.

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