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Regulation of eukaryotic aquaporins

Nyblom, Maria and Törnroth-Horsefield, Susanna LU (2016) p.53-76
Abstract

Membrane-bound water channels known as aquaporins (AQPs) facilitate water transport across biological membranes along osmotic gradients. Since all living cells depend on their ability to maintain water homeostasis, this must be tightly regulated. In eukaryotes, this is achieved by gating, which involves a conformational change of the protein, thereby physically blocking water transport, or by trafficking in which AQPs are shuttled between intracellular storage sites and the plasma membrane. Gating is common amongst plant AQPs in response to environmental stress and has been shown to be triggered by phosphorylation, pH and binding of divalent cations. Gating has been demonstrated for yeast AQPs for which it is believed to confer... (More)

Membrane-bound water channels known as aquaporins (AQPs) facilitate water transport across biological membranes along osmotic gradients. Since all living cells depend on their ability to maintain water homeostasis, this must be tightly regulated. In eukaryotes, this is achieved by gating, which involves a conformational change of the protein, thereby physically blocking water transport, or by trafficking in which AQPs are shuttled between intracellular storage sites and the plasma membrane. Gating is common amongst plant AQPs in response to environmental stress and has been shown to be triggered by phosphorylation, pH and binding of divalent cations. Gating has been demonstrated for yeast AQPs for which it is believed to confer protection against osmotic shock and rapid freezing. In mammals, AQP regulation is mainly achieved through trafficking. Thirteen AQPs have been identified in humans, the majority of which are regulated by trafficking in response to a wide range of stimuli. The far best characterized trafficking mechanism is that of AQP2 in the kidney collecting duct where it plays a key role in urine concentration. AQP2 trafficking is controlled by the pituitary hormone vasopressin that stimulates phosphorylation of the AQP2 C-terminus, triggering translocation of AQP2 from intracellular storage vesicles to the apical membrane. Defective trafficking of human AQPs can lead to several disease states, for example nephrogenic diabetes insipidus (AQP2) and Sjögren's syndrome (AQP5). In this chapter, we give an overview of what is known about the regulation of eukaryotic AQPs, focusing particularly on structure-function relationships. We discuss the physiological role of AQP regulation, specific regulatory mechanisms and reoccurring themes in both gating and trafficking.

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Please use this url to cite or link to this publication:
author
and
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
host publication
Aquaporins in Health and Disease : New Molecular Targets for Drug Discovery - New Molecular Targets for Drug Discovery
editor
Soveral, Graca ; Nielsen, Soren and Casini, Angela
pages
24 pages
publisher
CRC Press
external identifiers
  • scopus:85052333747
ISBN
9781498707831
9781498707848
language
English
LU publication?
yes
id
25edc787-1095-4996-9533-4f45f2d0528e
alternative location
https://www.taylorfrancis.com/books/e/9781498707848
date added to LUP
2018-10-01 10:33:15
date last changed
2024-06-10 18:13:59
@inbook{25edc787-1095-4996-9533-4f45f2d0528e,
  abstract     = {{<p>Membrane-bound water channels known as aquaporins (AQPs) facilitate water transport across biological membranes along osmotic gradients. Since all living cells depend on their ability to maintain water homeostasis, this must be tightly regulated. In eukaryotes, this is achieved by gating, which involves a conformational change of the protein, thereby physically blocking water transport, or by trafficking in which AQPs are shuttled between intracellular storage sites and the plasma membrane. Gating is common amongst plant AQPs in response to environmental stress and has been shown to be triggered by phosphorylation, pH and binding of divalent cations. Gating has been demonstrated for yeast AQPs for which it is believed to confer protection against osmotic shock and rapid freezing. In mammals, AQP regulation is mainly achieved through trafficking. Thirteen AQPs have been identified in humans, the majority of which are regulated by trafficking in response to a wide range of stimuli. The far best characterized trafficking mechanism is that of AQP2 in the kidney collecting duct where it plays a key role in urine concentration. AQP2 trafficking is controlled by the pituitary hormone vasopressin that stimulates phosphorylation of the AQP2 C-terminus, triggering translocation of AQP2 from intracellular storage vesicles to the apical membrane. Defective trafficking of human AQPs can lead to several disease states, for example nephrogenic diabetes insipidus (AQP2) and Sjögren's syndrome (AQP5). In this chapter, we give an overview of what is known about the regulation of eukaryotic AQPs, focusing particularly on structure-function relationships. We discuss the physiological role of AQP regulation, specific regulatory mechanisms and reoccurring themes in both gating and trafficking.</p>}},
  author       = {{Nyblom, Maria and Törnroth-Horsefield, Susanna}},
  booktitle    = {{Aquaporins in Health and Disease : New Molecular Targets for Drug Discovery}},
  editor       = {{Soveral, Graca and Nielsen, Soren and Casini, Angela}},
  isbn         = {{9781498707831}},
  language     = {{eng}},
  month        = {{01}},
  pages        = {{53--76}},
  publisher    = {{CRC Press}},
  title        = {{Regulation of eukaryotic aquaporins}},
  url          = {{https://www.taylorfrancis.com/books/e/9781498707848}},
  year         = {{2016}},
}