ArticleThe Journal of general physiology2000
Permeation properties of inward-rectifier potassium channels and their molecular determinants.
Article in The Journal of general physiology, 2000. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 37 papers.
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Who cites it
37 citing papers in PubMed, 90 citations in OpenAlex.
- Characterization of hyperactive mutations in the renal potassium channel ROMK uncovers unique effects on channel biogenesis and ion conductance.Molecular biology of the cell · 2024Article
- Conformational changes upon gating of KirBac1.1 into an open-activated state revealed by solid-state NMR and functional assays.Proceedings of the National Academy of Sciences of the United States of America · 2020Article
- NBCe1-A is required for the renal ammonia and KAmerican journal of physiology. Renal physiology · 2020Article
- An in vitro analysis of intestinal ammonia transport in fasted and fed freshwater rainbow trout: roles of NKCC, KJournal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2019Article
- Review
- Single-file transport of water through membrane channels.Faraday discussions · 2018Article
- Epithelial transport inThe Journal of general physiology · 2017Review
- Ammonia Transporters and Their Role in Acid-Base Balance.Physiological reviews · 2017Review
- Aquaporin 4 as a NH3 Channel.The Journal of biological chemistry · 2016Article
- Interactions of external K+ and internal blockers in a weak inward-rectifier K+ channel.The Journal of general physiology · 2012Article
- Ion selectivity and current saturation in inward-rectifier K+ channels.The Journal of general physiology · 2012Article
- Multiple functions of the crustacean gill: osmotic/ionic regulation, acid-base balance, ammonia excretion, and bioaccumulation of toxic metals.Frontiers in physiology · 2012Article
- Potassium deprivation: a systems approach.American journal of physiology. Renal physiology · 2011Article
- A mathematical model of rat ascending Henle limb. II. Epithelial function.American journal of physiology. Renal physiology · 2010Article
- A mathematical model of rat ascending Henle limb. I. Cotransporter function.American journal of physiology. Renal physiology · 2010Article
- Cardiac strong inward rectifier potassium channels.Journal of molecular and cellular cardiology · 2010Review
- Ammonia production, excretion, toxicity, and defense in fish: a review.Frontiers in physiology · 2010Article
- A comprehensive guide to the ROMK potassium channel: form and function in health and disease.American journal of physiology. Renal physiology · 2009Review
- Charges in the cytoplasmic pore control intrinsic inward rectification and single-channel properties in Kir1.1 and Kir2.1 channels.The Journal of membrane biology · 2007Article
- Molecular mechanisms of renal ammonia transport.Annual review of physiology · 2007Review
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Authors and funding
3 authors at 2 institutions in 1 country.
Funding
Abstract
The structural domains contributing to ion permeation and selectivity in K channels were examined in inward-rectifier K(+) channels ROMK2 (Kir1.1b), IRK1 (Kir2.1), and their chimeras using heterologous expression in Xenopus oocytes. Patch-clamp recordings of single channels were obtained in the cell-attached mode with different permeant cations in the pipette. For inward K(+) conduction, replacing the extracellular loop of ROMK2 with that of IRK1 increased single-channel conductance by 25 pS (from 39 to 63 pS), whereas replacing the COOH terminus of ROMK2 with that of IRK1 decreased conductance by 16 pS (from 39 to 22 pS). These effects were additive and independent of the origin of the NH(2) terminus or transmembrane domains, suggesting that the two domains form two resistors in series. The larger conductance of the extracellular loop of IRK1 was attributable to a single amino acid difference (Thr versus Val) at the 3P position, three residues in front of the GYG motif. Permeability sequences for the conducted ions were similar for the two channels: Tl(+) > K(+) > Rb(+) > NH(4)(+). The ion selectivity sequence for ROMK2 based on conductance ratios was NH(4)(+) (1.6) > K(+) (1) > Tl(+) (0.5) > Rb(+) (0.4). For IRK1, the sequence was K(+) (1) > Tl(+) (0.8) > NH(4)(+) (0.6) >> Rb(+) (0.1). The difference in the NH(4)(+)/ K(+) conductance (1.6) and permeability (0.09) ratios can be explained if NH(4)(+) binds with lower affinity than K(+) to sites within the pore. The relatively low conductances of NH(4)(+) and Rb(+) through IRK1 were again attributable to the 3P position within the P region. Site-directed mutagenesis showed that the IRK1 selectivity pattern required either Thr or Ser at this position. In contrast, the COOH-terminal domain conferred the relatively high Tl(+) conductance in IRK1. We propose that the P-region and the COOH terminus contribute independently to the conductance and selectivity properties of the pore.
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