TU Darmstadt / ULB / TUbiblio

Aquaporins and membrane diffusion of CO2 in living organisms.

Kaldenhoff, Ralf and Kai, Lei and Uehlein, Norbert (2014):
Aquaporins and membrane diffusion of CO2 in living organisms.
In: Biochimica et biophysica acta, pp. 1592-5, 1840, (5), ISSN 0006-3002, [Article]

Abstract

BACKGROUND

Determination of CO2 diffusion rates in living cells revealed inconsistencies with existing models about the mechanisms of membrane gas transport. Mainly, these discrepancies exist in the determined CO2 diffusion rates of bio-membranes, which were orders of magnitudes below those for pure lipid bilayers or theoretical considerations as well as in the observation that membrane insertion of specific aquaporins was rescuing high CO2 transport rates. This effect was confirmed by functional aquaporin protein analysis in heterologous expression systems as well as in bacteria, plants and partly in mammals.

SCOPE OF REVIEW

This review summarizes the arguments in favor of and against aquaporin facilitated membrane diffusion of CO2 and reports about its importance for the physiology of living organisms.

MAJOR CONCLUSIONS

Most likely, the aquaporin tetramer forming an additional fifth pore is required for CO2 diffusion facilitation. Aquaporin tetramer formation, membrane integration and disintegration could provide a mechanism for regulation of cellular CO2 exchange. The physiological importance of aquaporin mediated CO2 membrane diffusion could be shown for plants and cyanobacteria and partly for mammals.

GENERAL SIGNIFICANCE

Taking the mentioned results into account, consequences for our current picture of cell membrane transport emerge. It appears that in some or many instances, membranes might not be as permeable as it was suggested by current bio-membrane models, opening an additional way of controlling the cellular influx or efflux of volatile substances like CO2. This article is part of a Special Issue entitled Aquaporins.

Item Type: Article
Erschienen: 2014
Creators: Kaldenhoff, Ralf and Kai, Lei and Uehlein, Norbert
Title: Aquaporins and membrane diffusion of CO2 in living organisms.
Language: English
Abstract:

BACKGROUND

Determination of CO2 diffusion rates in living cells revealed inconsistencies with existing models about the mechanisms of membrane gas transport. Mainly, these discrepancies exist in the determined CO2 diffusion rates of bio-membranes, which were orders of magnitudes below those for pure lipid bilayers or theoretical considerations as well as in the observation that membrane insertion of specific aquaporins was rescuing high CO2 transport rates. This effect was confirmed by functional aquaporin protein analysis in heterologous expression systems as well as in bacteria, plants and partly in mammals.

SCOPE OF REVIEW

This review summarizes the arguments in favor of and against aquaporin facilitated membrane diffusion of CO2 and reports about its importance for the physiology of living organisms.

MAJOR CONCLUSIONS

Most likely, the aquaporin tetramer forming an additional fifth pore is required for CO2 diffusion facilitation. Aquaporin tetramer formation, membrane integration and disintegration could provide a mechanism for regulation of cellular CO2 exchange. The physiological importance of aquaporin mediated CO2 membrane diffusion could be shown for plants and cyanobacteria and partly for mammals.

GENERAL SIGNIFICANCE

Taking the mentioned results into account, consequences for our current picture of cell membrane transport emerge. It appears that in some or many instances, membranes might not be as permeable as it was suggested by current bio-membrane models, opening an additional way of controlling the cellular influx or efflux of volatile substances like CO2. This article is part of a Special Issue entitled Aquaporins.

Journal or Publication Title: Biochimica et biophysica acta
Volume: 1840
Number: 5
Divisions: 10 Department of Biology
10 Department of Biology > Applied Plant Sciences
Date Deposited: 29 Oct 2013 12:29
Export:

Optionen (nur für Redakteure)

View Item View Item