Rapid inactivation of the Escherichia coli Kdp K+ uptake system by high potassium concentrations

A J Roe, D McLaggan, C P O'Byrne, I R Booth

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The Kdp K+ uptake system of Escherichia coli is induced by limitation for K+ and/or high osmolarity. In the present study, the regulation of the activity of the Kdp system has been investigated in E. coli mutants possessing only the Kdp system as the mechanism of K+ accumulation. Cells grown in the presence of low K+ (0.1-1 mM) exhibit normal growth. However, growth inhibition results from exposure of cells to moderate levels of external K+ (> 5 mM). Measurement of the cytoplasmic pH, of K+ pools and of transport via the Kdp system demonstrates that the Kdp system is rapidly and irreversibly inhibited by moderate external K+. Concentrations of K+ greater than 2 mM are sufficient to cause inhibition of Kdp. At pH 6, this results in rapid lowering of the capacity for pH homeostasis, but at pH 7 the intracellular pH is unaffected. Parallel analysis of the expression of the Kdp system in a Kdp(+)/kdpFABC-lacZ strain shows that levels of K+ that are sufficient to inhibit Kdp activity also repress expression. As a result, growth inhibition of strains solely possessing Kdp arises jointly from inhibition of Kdp activity and repression of Kdp gene expression. These data identify an important aspect of the regulation of potassium transport via the Kdp system and also provide support for a model of regulation of Kdp expression via at least two mechanisms: sensing of both turgor and external K+ concentration.

Original languageEnglish
Pages (from-to)1235-1243
Number of pages9
JournalMolecular Microbiology
Volume35
Publication statusPublished - 2000

Keywords

  • OPERON EXPRESSION
  • CATION-TRANSPORT
  • ATPASE
  • OSMOREGULATION
  • ACCUMULATION
  • TURGOR
  • SIGNAL
  • GROWTH
  • PH

Cite this

Roe, A. J., McLaggan, D., O'Byrne, C. P., & Booth, I. R. (2000). Rapid inactivation of the Escherichia coli Kdp K+ uptake system by high potassium concentrations. Molecular Microbiology, 35, 1235-1243.

Rapid inactivation of the Escherichia coli Kdp K+ uptake system by high potassium concentrations. / Roe, A J ; McLaggan, D ; O'Byrne, C P ; Booth, I R .

In: Molecular Microbiology, Vol. 35, 2000, p. 1235-1243.

Research output: Contribution to journalArticle

Roe, AJ, McLaggan, D, O'Byrne, CP & Booth, IR 2000, 'Rapid inactivation of the Escherichia coli Kdp K+ uptake system by high potassium concentrations', Molecular Microbiology, vol. 35, pp. 1235-1243.
Roe, A J ; McLaggan, D ; O'Byrne, C P ; Booth, I R . / Rapid inactivation of the Escherichia coli Kdp K+ uptake system by high potassium concentrations. In: Molecular Microbiology. 2000 ; Vol. 35. pp. 1235-1243.
@article{5e6d53ef405d429a9ed6e9c3072f868e,
title = "Rapid inactivation of the Escherichia coli Kdp K+ uptake system by high potassium concentrations",
abstract = "The Kdp K+ uptake system of Escherichia coli is induced by limitation for K+ and/or high osmolarity. In the present study, the regulation of the activity of the Kdp system has been investigated in E. coli mutants possessing only the Kdp system as the mechanism of K+ accumulation. Cells grown in the presence of low K+ (0.1-1 mM) exhibit normal growth. However, growth inhibition results from exposure of cells to moderate levels of external K+ (> 5 mM). Measurement of the cytoplasmic pH, of K+ pools and of transport via the Kdp system demonstrates that the Kdp system is rapidly and irreversibly inhibited by moderate external K+. Concentrations of K+ greater than 2 mM are sufficient to cause inhibition of Kdp. At pH 6, this results in rapid lowering of the capacity for pH homeostasis, but at pH 7 the intracellular pH is unaffected. Parallel analysis of the expression of the Kdp system in a Kdp(+)/kdpFABC-lacZ strain shows that levels of K+ that are sufficient to inhibit Kdp activity also repress expression. As a result, growth inhibition of strains solely possessing Kdp arises jointly from inhibition of Kdp activity and repression of Kdp gene expression. These data identify an important aspect of the regulation of potassium transport via the Kdp system and also provide support for a model of regulation of Kdp expression via at least two mechanisms: sensing of both turgor and external K+ concentration.",
keywords = "OPERON EXPRESSION, CATION-TRANSPORT, ATPASE, OSMOREGULATION, ACCUMULATION, TURGOR, SIGNAL, GROWTH, PH",
author = "Roe, {A J} and D McLaggan and O'Byrne, {C P} and Booth, {I R}",
year = "2000",
language = "English",
volume = "35",
pages = "1235--1243",
journal = "Molecular Microbiology",
issn = "0950-382X",
publisher = "Wiley-Blackwell",

}

TY - JOUR

T1 - Rapid inactivation of the Escherichia coli Kdp K+ uptake system by high potassium concentrations

AU - Roe, A J

AU - McLaggan, D

AU - O'Byrne, C P

AU - Booth, I R

PY - 2000

Y1 - 2000

N2 - The Kdp K+ uptake system of Escherichia coli is induced by limitation for K+ and/or high osmolarity. In the present study, the regulation of the activity of the Kdp system has been investigated in E. coli mutants possessing only the Kdp system as the mechanism of K+ accumulation. Cells grown in the presence of low K+ (0.1-1 mM) exhibit normal growth. However, growth inhibition results from exposure of cells to moderate levels of external K+ (> 5 mM). Measurement of the cytoplasmic pH, of K+ pools and of transport via the Kdp system demonstrates that the Kdp system is rapidly and irreversibly inhibited by moderate external K+. Concentrations of K+ greater than 2 mM are sufficient to cause inhibition of Kdp. At pH 6, this results in rapid lowering of the capacity for pH homeostasis, but at pH 7 the intracellular pH is unaffected. Parallel analysis of the expression of the Kdp system in a Kdp(+)/kdpFABC-lacZ strain shows that levels of K+ that are sufficient to inhibit Kdp activity also repress expression. As a result, growth inhibition of strains solely possessing Kdp arises jointly from inhibition of Kdp activity and repression of Kdp gene expression. These data identify an important aspect of the regulation of potassium transport via the Kdp system and also provide support for a model of regulation of Kdp expression via at least two mechanisms: sensing of both turgor and external K+ concentration.

AB - The Kdp K+ uptake system of Escherichia coli is induced by limitation for K+ and/or high osmolarity. In the present study, the regulation of the activity of the Kdp system has been investigated in E. coli mutants possessing only the Kdp system as the mechanism of K+ accumulation. Cells grown in the presence of low K+ (0.1-1 mM) exhibit normal growth. However, growth inhibition results from exposure of cells to moderate levels of external K+ (> 5 mM). Measurement of the cytoplasmic pH, of K+ pools and of transport via the Kdp system demonstrates that the Kdp system is rapidly and irreversibly inhibited by moderate external K+. Concentrations of K+ greater than 2 mM are sufficient to cause inhibition of Kdp. At pH 6, this results in rapid lowering of the capacity for pH homeostasis, but at pH 7 the intracellular pH is unaffected. Parallel analysis of the expression of the Kdp system in a Kdp(+)/kdpFABC-lacZ strain shows that levels of K+ that are sufficient to inhibit Kdp activity also repress expression. As a result, growth inhibition of strains solely possessing Kdp arises jointly from inhibition of Kdp activity and repression of Kdp gene expression. These data identify an important aspect of the regulation of potassium transport via the Kdp system and also provide support for a model of regulation of Kdp expression via at least two mechanisms: sensing of both turgor and external K+ concentration.

KW - OPERON EXPRESSION

KW - CATION-TRANSPORT

KW - ATPASE

KW - OSMOREGULATION

KW - ACCUMULATION

KW - TURGOR

KW - SIGNAL

KW - GROWTH

KW - PH

M3 - Article

VL - 35

SP - 1235

EP - 1243

JO - Molecular Microbiology

JF - Molecular Microbiology

SN - 0950-382X

ER -