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CO2 permeability of cell membranes is regulated by membrane cholesterol and protein gas channels

Itel, F. and Al-Samir, S. and Oberg, F. and Chami, M. and Kumar, M. and Supuran, C. T. and Deen, P. M. T. and Meier, W. and Hedfalk, K. and Gros, G. and Endeward, V.. (2012) CO2 permeability of cell membranes is regulated by membrane cholesterol and protein gas channels. The FASEB Journal, Vol. 26, H. 12. pp. 5182-5191.

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Official URL: http://edoc.unibas.ch/dok/A6070456

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Abstract

Recent observations that some membrane proteins act as gas channels seem surprising in view of the classical concept that membranes generally are highly permeable to gases. Here, we study the gas permeability of membranes for the case of CO2, using a previously established mass spectrometric technique. We first show that biological membranes lacking protein gas channels but containing normal amounts of cholesterol (30-50 mol% of total lipid), e.g., MDCK and tsA201 cells, in fact possess an unexpectedly low CO2 permeability (PCO2) of similar to 0.01 cm/s, which is 2 orders of magnitude lower than the PCO2 of pure planar phospholipid bilayers (similar to 1 cm/s). Phospholipid vesicles enriched with similar amounts of cholesterol also exhibit PCO2 approximate to 0.01 cm/s, identifying cholesterol as the major determinant of membrane PCO2. This is confirmed by the demonstration that MDCK cells depleted of or enriched with membrane cholesterol show dramatic increases or decreases in PCO2, respectively. We demonstrate, furthermore, that reconstitution of human AQP-1 into cholesterol-containing vesicles, as well as expression of human AQP-1 in MDCK cells, leads to drastic increases in PCO2, indicating that gas channels are of high functional significance for gas transfer across membranes of low intrinsic gas permeability.-Itel, F., Al-Samir, S., Oberg, F., Chami, M., Kumar, M., Supuran, C. T., Deen, P. M. T., Meier, W., Hedfalk, K., Gros, G., Endeward, V. CO2 permeability of cell membranes is regulated by membrane cholesterol and protein gas channels. FASEB J. 26, 5182-5191 (2012). www.fasebj.org
Faculties and Departments:05 Faculty of Science > Departement Chemie
05 Faculty of Science > Departement Chemie > Chemie > Makromolekulare Chemie (Meier)
UniBasel Contributors:Meier, Wolfgang P. and Itel, Fabian
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:FASEB
ISSN:0892-6638
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:01 Mar 2013 11:14
Deposited On:01 Mar 2013 11:12

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