ArticleThe Plant cell2002
Outer pore residues control the H(+) and K(+) sensitivity of the Arabidopsis potassium channel AKT3.
Article in The Plant cell, 2002. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 17 papers.
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Who cites it
17 citing papers in PubMed, 39 citations in OpenAlex.
- EgKT2-1, an inwardly rectifying Shaker-type potassium channel in oil palm that correlates with oil yield.Plant cell reports · 2026Article
- Genome-wide identification and analysis of TCP family genes in Medicago sativa reveal their critical roles in NaBMC plant biology · 2023Article
- A novel calcium binding site in the slow vacuolar cation channel TPC1 senses luminal calcium levels.The Plant cell · 2011Article
- Defensin-like ZmES4 mediates pollen tube burst in maize via opening of the potassium channel KZM1.PLoS biology · 2010Article
- Inhibition of K(Ca)2.2 and K(Ca)2.3 channel currents by protonation of outer pore histidine residues.The Journal of general physiology · 2009Article
- Proton inhibition of unitary currents of vanilloid receptors.The Journal of general physiology · 2009Article
- Heteromeric AtKC1{middle dot}AKT1 channels in Arabidopsis roots facilitate growth under K+-limiting conditions.The Journal of biological chemistry · 2009Article
- Heteromerization of Arabidopsis Kv channel alpha-subunits: Data and prospects.Plant signaling & behavior · 2008Article
- In planta AKT2 subunits constitute a pH- and Ca2+-sensitive inward rectifying K+ channel.Planta · 2007Article
- Mutation of His-157 in the second pore loop drastically reduces the activity of the Synechocystis Ktr-type transporter.Journal of bacteriology · 2006Article
- 30-year progress of membrane transport in plants.Planta · 2006Review
- Properties of shaker-type potassium channels in higher plants.The Journal of membrane biology · 2006Review
- Interactive domains between pore loops of the yeast K+ channel TOK1 associate with extracellular K+ sensitivity.The Biochemical journal · 2006Article
- A unique voltage sensor sensitizes the potassium channel AKT2 to phosphoregulation.The Journal of general physiology · 2005Article
- AKT2/3 subunits render guard cell K+ channels Ca2+ sensitive.The Journal of general physiology · 2005Article
- Regulation by external K+ in a maize inward shaker channel targets transport activity in the high concentration range.The Plant cell · 2005Article
- Protons block BK channels by competitive inhibition with K+ and contribute to the limits of unitary currents at high voltages.The Journal of general physiology · 2004Article
Corrections and comments
- Erratum issued
Authors and funding
4 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The Arabidopsis phloem channel AKT3 is the founder of a subfamily of shaker-like plant potassium channels characterized by weak rectification, Ca(2+) block, proton inhibition, and, as shown in this study, K(+) sensitivity. In contrast to inward-rectifying, acid-activated K(+) channels of the KAT1 family, extracellular acidification decreases AKT3 currents at the macroscopic and single-channel levels. Here, we show that two distinct sites within the outer mouth of the K(+)-conducting pore provide the molecular basis for the pH sensitivity of this phloem channel. After generation of mutant channels and functional expression in Xenopus oocytes, we identified the His residue His-228, which is proximal to the K(+) selectivity filter (GYGD) and the distal Ser residue Ser-271, to be involved in proton susceptibility. Mutations of these sites, H228D and S271E, drastically reduced the H(+) and K(+) sensitivity of AKT3. Although in K(+)-free bath solutions outward K(+) currents were abolished completely in wild-type AKT3, S271E as well as the AKT3-HDSE double mutant still mediated K(+) efflux. We conclude that the pH- and K(+)-dependent properties of the AKT3 channel involve residues in the outer mouth of the pore. Both properties, H(+) and K(+) sensitivity, allow the fine-tuning of the phloem channel and thus seem to represent important elements in the control of membrane potential and sugar loading.
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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.