Interactions of Xenobiotics with Ion Transporters

2007 ◽  
pp. 301-308
Keyword(s):  
Ion Transporters

New therapeutical targets in ulcerative colitis: the importance of ion transporters in the human colon

2010 ◽  
Vol 48 (05) ◽  
Author(s):  
K Farkas ◽  
Z Rakonczay Jr ◽  
F Nagy ◽  
T Molnár ◽  
Z Szepes ◽  
...  
Keyword(s):  
Ulcerative Colitis ◽  
Human Colon ◽  
Ion Transporters

Crown ether-thiourea conjugates as ion transporters

2021 ◽  
Author(s):  
Zhixing Zhao ◽  
Bailing Tang ◽  
Xiaosheng Yan ◽  
Xin Wu ◽  
Zhao Li ◽  
...  
Keyword(s):  
Crown Ether ◽  
Ion Transporters

scholarly journals A Novel Six-Rhodopsin System in a Single Archaeon

2010 ◽  
Vol 192 (22) ◽  
pp. 5866-5873 ◽  
Author(s):  
Hsu-Yuan Fu ◽  
Yu-Cheng Lin ◽  
Yung-Ning Chang ◽  
Hsiaochu Tseng ◽  
Ching-Che Huang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Global Environment ◽  
Diverse Group ◽  
Ion Transporters ◽  
Haloarcula Marismortui ◽  
Resource Limited ◽  
New Type ◽  
Ion Transportation ◽  
Proton Transporters ◽  
First Time

ABSTRACT Microbial rhodopsins, a diverse group of photoactive proteins found in Archaea, Bacteria, and Eukarya, function in photosensing and photoenergy harvesting and may have been present in the resource-limited early global environment. Four different physiological functions have been identified and characterized for nearly 5,000 retinal-binding photoreceptors, these being ion transporters that transport proton or chloride and sensory rhodopsins that mediate light-attractant and/or -repellent responses. The greatest number of rhodopsins previously observed in a single archaeon had been four. Here, we report a newly discovered six-rhodopsin system in a single archaeon, Haloarcula marismortui, which shows a more diverse absorbance spectral distribution than any previously known rhodopsin system, and, for the first time, two light-driven proton transporters that respond to the same wavelength. All six rhodopsins, the greatest number ever identified in a single archaeon, were first shown to be expressed in H. marismortui, and these were then overexpressed in Escherichia coli. The proteins were purified for absorption spectra and photocycle determination, followed by measurement of ion transportation and phototaxis. The results clearly indicate the existence of a proton transporter system with two isochromatic rhodopsins and a new type of sensory rhodopsin-like transducer in H. marismortui.

scholarly journals Altered Expression and Localization of Ion Transporters Contribute to Diarrhea in Mice With Salmonella-Induced Enteritis

2013 ◽  
Vol 145 (6) ◽  
pp. 1358-1368.e4 ◽  
Author(s):  
Ronald R. Marchelletta ◽  
Melanie G. Gareau ◽  
Declan F. McCole ◽  
Sharon Okamoto ◽  
Elise Roel ◽  
...  
Keyword(s):  
Ion Transporters ◽  
Altered Expression

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 Gene Expression Levels and Immunolocalization of Organic Ion Transporters in the Human Kidney

2002 ◽  
Vol 13 (4) ◽  
pp. 866-874
Author(s):  
Hideyuki Motohashi ◽  
Yuji Sakurai ◽  
Hideyuki Saito ◽  
Satohiro Masuda ◽  
Yumiko Urakami ◽  
...  
Keyword(s):  
Basolateral Membrane ◽  
Mrna Level ◽  
Human Kidney ◽  
Proximal Tubules ◽  
Mrna Levels ◽  
Ion Transporters ◽  
Ion Transporter ◽  
Transporter Family ◽  
Immunohistochemical Analyses ◽  
Gene Expression Levels

ABSTRACT. Renal excretion of organic anions and cations is mediated by the organic ion transporter family (SLC22A). In this study, the mRNA levels of the organic ion transporters were quantified by real-time PCR in normal parts of renal tissues from seven nephrectomized patients with renal cell carcinoma, and the distributions and localization of human (h)OAT1, hOAT3, and hOCT2 proteins were investigated by immunohistochemical analyses in the human kidney. The expression level of hOAT3 mRNA was the highest among the organic ion transporter family, followed by that of hOAT1 mRNA. The hOCT2 mRNA level was the highest in the human OCT family, and the level of hOCTN2 mRNA was higher than that of hOCTN1. hOCT1 mRNA showed the lowest level of expression in organic ion transporter family. hOAT1, hOAT3, and hOCT2 proteins were detected in crude membranes from the kidney of all patients by Western blot analyses, whereas hOCT1 protein could not be detected. Immunohistochemical analyses showed that both hOAT1 and hOAT3 were localized to the basolateral membrane of the proximal tubules in the cortex, and hOCT2 was localized to the basolateral membrane of the proximal tubules in both the cortex and medullary ray. Immunohistochemical analyses of serial sections indicated that hOAT1, hOAT3, and hOCT2 were coexpressed in a portion of the proximal tubules. These results suggest that hOAT1, hOAT3, and hOCT2 play predominant roles in the transport of organic ions across the basolateral membrane of human proximal tubules.

scholarly journals Regulation of Root Ion Transporters by Photosynthesis: Functional Importance and Relation with Hexokinase

2003 ◽  
Vol 15 (9) ◽  
pp. 2218-2232 ◽  
Author(s):  
Laurence Lejay ◽  
Xavier Gansel ◽  
Miguel Cerezo ◽  
Pascal Tillard ◽  
Cathrin Müller ◽  
...  
Keyword(s):  
Ion Transporters ◽  
Functional Importance
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