Metallomics and the Cell pp 41-67

Part of the Metal Ions in Life Sciences book series (MILS, volume 12)

Sodium/Potassium Homeostasis in the Cell

  • Michael Jakob Voldsgaard Clausen
  • Hanne Poulsen

Abstract

All animals are characterized by steep gradients of Na+ and K+ across the plasma membrane, and in spite of their highly similar chemical properties, the ions can be distinguished by numerous channels and transporters. The gradients are generated by the Na+,K+-ATPase, or sodium pump, which pumps out Na+ and takes up K+ at the expense of the chemical energy from ATP. Because the membrane is more permeable to K+ than to Na+, the uneven ion distribution causes a transmembrane voltage difference, and this membrane potential forms the basis for the action potential and for much of the neuronal signaling in general. The potential energy stored in the concentration gradients is also used to drive a large number of the secondary transporters responsible for transmembrane carriage of solutes ranging from sugars, amino acids, and neurotransmitters to inorganic ions such as chloride, inorganic phosphate, and bicarbonate. Furthermore, Na+ and K+ themselves are important enzymatic cofactors that typically lower the energy barrier of substrate binding.

In this chapter, we describe the roles of Na+ and K+ in the animal cell with emphasis on the creation and usage of the steep gradients across the membrane. More than 50 years of Na+,K+-ATPase research has revealed many details of the molecular machinery and offered insights into how the pump is regulated by post-translational modifications and specific drugs.

Keywords

action potential ion gradients membrane potential Na+ and K+ homeostasis ouabain palytoxin renal tubular system secondary transporters sodium pump voltage-gated channels Please cite as: Met. Ions Life Sci. 12 (2013) 41–67 

Abbreviations

A-domain

actuator domain

ADP

adenosine 5’-diphosphate

AMPA

2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid

ATP

adenosine 5’-triphosphate

CCCs

cation-chloride co-transporters

CNS

central nervous system

EAATs

excitatory amino acid transporters

ER

endoplasmic reticulum

FHM2

familial hemeplegic migraine 2

GABA

γ-aminobutyric acid

GLUTs

glucose transporters

KCCs

K+-coupled Cl exporters

Kv

voltage-gated K+ channels

LD50

lethal dose, 50%

LeuT

leucine transporter

nAchR

nicotinic acetylcholine receptor

NaPi

Na+-coupled Pi symporter

Nav

voltage-gated Na+ channels

Nax

subfamily of voltage-gated sodium channels (formerly Nav2.1 in humans)

NCBTs

sodium-coupled bicarbonate transporters

NCCs

Na+-coupled Cl importers

N-domain

nucleotide-binding domain

NHEs

Na+-coupled H+ exporters

NKCCs

Na+-coupled K+ and Cl importers

NSSs

neurotransmitter sodium symporters

P-domain

phosphorylation domain

Pi

inorganic phosphate

PKA

protein kinase A

PKC

protein kinase C

RDP

rapid-onset dystonia parkinsonism

SGLTs

sodium-dependent glucose transporters

SSRIs

selective serotonin re-uptake inhibitors

TMs

transmembrane helices

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Michael Jakob Voldsgaard Clausen
    • 1
  • Hanne Poulsen
    • 1
  1. 1.Centre for Structural Biology, Department of Molecular Biology and GeneticsUniversity of AarhusAarhus CDenmark

Personalised recommendations