Evidence map›Paper›PMID 19167319›Full record

ArticleBiophysical journal2009

Effects on conformational states of the rabbit sodium/glucose cotransporter through modulation of polarity and charge at glutamine 457.

Tiemin Liu, Daniel Krofchick, Mel Silverman

Open access · bronzeAbstract read
In one paragraph

Article in Biophysical journal, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing papers in PubMed
0.4field-weighted citation impact, top 37% of its field
1 · What the graph read from it

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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

4 citing papers in PubMed, 8 citations in OpenAlex.

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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors at 1 institution in 1 country.

Tiemin LiuDepartment of Medicine, University of Toronto, Toronto, Ontario, Canada.
Daniel Krofchick
Mel Silverman
University of Toronto · CA

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The high affinity sodium/glucose cotransporter (SGLT1) couples transport of Na(+) and glucose. Previous studies established that mutant Q457C human SGLT1 retains full activity, and sugar translocation is abolished in mutant Q457R or in mutant Q457C after reaction with methanethiosulfonate derivatives, but Na(+) and sugar binding remain intact. To explore the mechanism by which modulation of Q457 abolishes transport, Q457C and Q457R of rabbit SGLT1 were studied using chemical modification and the two-electrode voltage-clamp technique. Compared to wild-type SGLT1, Q457C exhibits approximately 20-fold reduction in phloridzin affinity and preferential occupancy of an inward-facing state. Alkylation of Q457C by [(2-trimethylammonium) ethyl] methanethiosulphonate bromide, (MTSET), reverses these changes while blocking transport. Analysis of pre-steady-state currents in the absence of sugar yields three decay constants for each of Q457C, Q457C-MTSET and Q457R. Comparison of Q457C-MTSET and Q457R with Q457C and wild-type, reveals that inhibition of transport is accompanied by a decrease in magnitude and voltage-independence of the slow decay constant at negative potentials. But fast and medium decays remain unchanged. Computer simulation of transient currents suggests that introduction of positive charge at position 457 leads to a predominant outward rather than inward-facing conformational state. Taken together, the results suggest that glutamine 457, in addition to being involved in sugar binding, is a residue that is sensitive to conformational changes of the carrier.

Indexed as

AlkylationAnimalsCarbohydrate MetabolismComputer SimulationGlutamineIonsKineticsMembrane PotentialsMesylatesModels, BiologicalMutation, MissenseOocytesPatch-Clamp TechniquesPhlorhizinProtein ConformationRabbits(2-(trimethylammonium)ethyl)methanethiosulfonateGlutamineIonsMesylatesPhlorhizinSodium-Glucose Transporter 1

Identifiers

PMID19167319
PMCPMC2716465
OpenAlexW2055847083

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

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.