Identification of a pH regulated Na+/H+ antiporter of Methanococcus jannaschii

Hellmer, Jens; Pätzold, Ralf; Zeilinger, Carsten

doi:10.1016/s0014-5793(02)03244-1

Cited by 23 publications

(24 citation statements)

References 27 publications

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“…MjNhaP1 has been found to be inactive at pH above 7.5 (4, 15). Using conditions where the pH was kept at 7.5 on both sides of the membrane, proteoliposomes adsorbed to the SSM gave rise to a fast positive transient current in response to Na + (ΔNa) or Li + (ΔLi) concentration jumps (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Keeping It Simple, Transport Mechanism and pH Regulation in Na+/H+ Exchangers

Călinescu

Kühlbrandt

Fendler

2014

Journal of Biological Chemistry

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Background: Na+/H+ exchangers have a pronounced pH dependence previously explained by pH sensors.Results: Electrophysiological investigation of NhaP1 from Methanocaldococcus jannaschii (MjNhaP1), a prototype of electroneutral Na+/H+ exchangers, allowed its kinetic characterization.Conclusion: The pH dependence of Na+/H+ exchangers is an inherent property of their transport mechanism.Significance: The proposed mechanism of transport and pH regulation applies to all Na+/H+ exchangers.

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Section: Resultsmentioning

confidence: 99%

“…The pH dependence of MjNhaP1 transport has previously been investigated in everted vesicles by acridine orange dequenching (15), an assay that only works above pH 6. To examine transport activity in the pH range 5–8 (as for the SSM experiments), we monitored Na + efflux by atomic absorption spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

Keeping It Simple, Transport Mechanism and pH Regulation in Na+/H+ Exchangers

Călinescu

Kühlbrandt

Fendler

2014

Journal of Biological Chemistry

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“…NhaP is known to transport Na ϩ or Li ϩ in exchange for H ϩ in an electroneutral and pH-dependent manner (66, 69,79,149). Exogenously expressed ApNhaP from a halotolerant cyanobacterium conferred salt tolerance in a fresh water cyanobacterium (Synechococcus sp.…”

Section: The Cpa1 Familymentioning

confidence: 99%

Evolutionary origins of eukaryotic sodium/proton exchangers

Brett

Donowitz

Rao

2005

American Journal of Physiology-Cell Physiology

506

544

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Brett, Christopher L., Mark Donowitz, and Rajini Rao. Evolutionary origins of eukaryotic sodium/proton exchangers. Am J Physiol Cell Physiol 288: C223-C239, 2005; doi:10.1152/ajpcell.00360.2004.-More than 200 genes annotated as Na ϩ /H ϩ hydrogen exchangers (NHEs) currently reside in bioinformation databases such as GenBank and Pfam. We performed detailed phylogenetic analyses of these NHEs in an effort to better understand their specific functions and physiological roles. This analysis initially required examining the entire monovalent cation proton antiporter (CPA) superfamily that includes the CPA1, CPA2, and NaT-DC families of transporters, each of which has a unique set of bacterial ancestors. We have concluded that there are nine human NHE (or SLC9A) paralogs as well as two previously unknown human CPA2 genes, which we have named HsNHA1 and HsNHA2. The eukaryotic NHE family is composed of five phylogenetically distinct clades that differ in subcellular location, drug sensitivity, cation selectivity, and sequence length. The major subgroups are plasma membrane (recycling and resident) and intracellular (endosomal/TGN, NHE8-like, and plant vacuolar). HsNHE1, the first cloned eukaryotic NHE gene, belongs to the resident plasma membrane clade. The latter is the most recent to emerge, being found exclusively in vertebrates. In contrast, the intracellular clades are ubiquitously distributed and are likely precursors to the plasma membrane NHE. Yeast endosomal ScNHX1 was the first intracellular NHE to be described and is closely related to HsNHE6, HsNHE7, and HsNHE9 in humans. Our results link the appearance of NHE on the plasma membrane of animal cells to the use of the Na ϩ /K ϩ -ATPase to generate the membrane potential. These novel observations have allowed us to use comparative biology to predict physiological roles for the nine human NHE paralogs and to propose appropriate model organisms in which to study the unique properties of each NHE subclass. Naϩ /H ϩ exchanger; NHX; cation proton antiporter; phylogenetic analysis A BASIC PROPERTY OF LIFE is the ability of an organism to regulate cellular pH, volume, and ion composition. The transmembrane exchange of protons for sodium ions (Na ϩ ) is ubiquitous in organisms across all phyla and kingdoms, and underlies fundamental homeostatic mechanisms to control these ions. The family of Na ϩ /H ϩ exchangers (NHEs) plays an important role in diverse physiological processes, including control of cell cycle and cell proliferation (114, 117), transepithelial Na ϩ movement (174), salt tolerance (93, 130), vesicle trafficking, and biogenesis (5, 22). In mammals, NHE dysfunction is associated with pathophysiological conditions that include hypertension, epilepsy, postischemic myocardial arrhythmia, gastric and kidney disease, diarrhea, and glaucoma (36, 106, 174). Drugs such as S8218 and cariporide, which target specific NHE isoforms, are used to reduce the duration of apnea in animal studies and in clinical trials for the prevention of cardiac ischemia-reperfusion injur...

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“…As MjNhaP1 is active within pH 6.0-6.5 and inactive at pH 4.0 (Hellmer et al, 2002;Vinothkumar et al, 2005), we could perform AFM and SMFS experiments on both functional states of the protein. The experiments were carried out at pH 4.0 (20 mM K + -acetate, 150 mM KCl, and 50 mM NaCl) and pH 6.3 (20 mM MES, 150 mM KCl, and 50 mM NaCl).…”

Section: Sensing the Activation Of Single Antiportersmentioning

confidence: 99%

“…The genome of the thermophilic archeabacteria Methanococcus jannaschii (Bult et al, 1996) encodes three Na + /H + antiporters (Hellmer et al, 2002). Recent studies provided first functional and structural insights of one of the antiporters, MjNhaP1, which possesses a higher homology to eukaryotic Na + /H + exchangers than to NhaA (Hellmer et al, 2003).…”

Section: Introductionmentioning

confidence: 99%