ArticleThe Journal of general physiology1998
The voltage dependence of a cloned mammalian renal type II Na+/Pi cotransporter (NaPi-2).
Article in The Journal of general physiology, 1998. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 46 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
46 citing papers in PubMed, 108 citations in OpenAlex.
- Structures of the sodium-coupled phosphate importer SLC34A2 reveal a distinct architecture and gating mechanism.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- The Intricacies of Renal Phosphate Reabsorption-An Overview.International journal of molecular sciences · 2024Review
- Flux coupling, not specificity, shapes the transport and phylogeny of SLC6 glycine transporters.Proceedings of the National Academy of Sciences of the United States of America · 2022Article
- Potent Inhibition of Biphasic Tubular Reabsorption of Lithium by Acetazolamide and Foscarnet in Rats.Physiological research · 2020Article
- Mechanisms of phosphate transport.Nature reviews. Nephrology · 2019Review
- Distinct functional properties of two electrogenic isoforms of the SLC34 Na-Pi cotransporter.Physiological reports · 2019Article
- The molecular mechanism of SLC34 proteins: insights from two decades of transport assays and structure-function studies.Pflugers Archiv : European journal of physiology · 2019Review
- Substrates and inhibitors of phosphate transporters: from experimental tools to pathophysiological relevance.Pflugers Archiv : European journal of physiology · 2019Review
- Family resemblances: A common fold for some dimeric ion-coupled secondary transporters.The Journal of general physiology · 2015Article
- Identification of the first sodium binding site of the phosphate cotransporter NaPi-IIa (SLC34A1).Biophysical journal · 2015Article
- The sodium/multivitamin transporter: a multipotent system with therapeutic implications.Vitamins and hormones · 2015Review
- Structural fold and binding sites of the human Na⁺-phosphate cotransporter NaPi-II.Biophysical journal · 2014Article
- The SLC34 family of sodium-dependent phosphate transporters.Pflugers Archiv : European journal of physiology · 2014Review
- Conferring electrogenicity to the electroneutral phosphate cotransporter NaPi-IIc (SLC34A3) reveals an internal cation release step.Pflugers Archiv : European journal of physiology · 2013Article
- Conformational changes represent the rate-limiting step in the transport cycle of maize sucrose transporter1.The Plant cell · 2013Article
- Mechanism of proton/substrate coupling in the heptahelical lysosomal transporter cystinosin.Proceedings of the National Academy of Sciences of the United States of America · 2012Article
- Voltage- and substrate-dependent interactions between sites in putative re-entrant domains of a Na(+)-coupled phosphate cotransporter.Pflugers Archiv : European journal of physiology · 2011Article
- Sucrose- and H-dependent charge movements associated with the gating of sucrose transporter ZmSUT1.PloS one · 2010Article
- Effects of Na+ and H+ on steady-state and presteady-state currents of the human concentrative nucleoside transporter 3 (hCNT3).Pflugers Archiv : European journal of physiology · 2010Article
- The actual ionic nature of the leak current through the Na+/glucose cotransporter SGLT1.Biophysical journal · 2010Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The voltage dependence of the rat renal type II Na+/Pi cotransporter (NaPi-2) was investigated by expressing NaPi-2 in Xenopus laevis oocytes and applying the two-electrode voltage clamp. In the steady state, superfusion with inorganic phosphate (Pi) induced inward currents (Ip) in the presence of 96 mM Na+ over the potential range -140 </= V </= +40 mV. With Pi as the variable substrate, the apparent affinity constant (KmPi) was strongly dependent on Na+, increasing sixfold for a twofold reduction in external Na+. KmPi increased with depolarizing voltage and was more sensitive to voltage at reduced Na+. The Hill coefficient was close to unity and the predicted maximum Ip (Ipmax) was 40% smaller at 50 mM Na+. With Na+ as the variable substrate, KmNa was weakly dependent on both Pi and voltage, the Hill coefficient was close to 3 and Ipmax was independent of Pi at -50 mV. The competitive inhibitor phosphonoformic acid suppressed the steady state holding current in a Na+-dependent manner, indicating the existence of uncoupled Na+ slippage. Voltage steps induced pre-steady state relaxations typical for Na+-coupled cotransporters. NaPi-2-dependent relaxations were quantitated by a single, voltage-dependent exponential. At 96 mM Na+, a Boltzmann function was fit to the steady state charge distribution (Q-V) to give a midpoint voltage (V0.5) in the range -20 to -50 mV and an apparent valency of approximately 0.5 e-. V0.5 became more negative as Na+ was reduced. Pi suppressed relaxations in a dose-dependent manner, but had little effect on their voltage dependence. Reducing external pH shifted V0.5 to depolarizing potentials and suppressed relaxations in the absence of Na+, suggesting that protons interact with the unloaded carrier. These findings were incorporated into an ordered kinetic model whereby Na+ is the first and last substrate to bind, and the observed voltage dependence arises from the unloaded carrier and first Na+ binding step.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.