Intrinsic CO_2 permeability of cell membranes and potential biological relevance of CO_2 channels

摘要

The past dozen years has seen a series of papers that come to the conclusion that CO_2 passes through certain aquaporins and Rhesus proteins. The past three years has seen another series of papers that come to the conclusion that protein channels could not make a meaningful contribution to overall CO_2 membrane permeability because of a combination of: 1) a high CO_2 permeability of membrane lipids and 2) large unstirred layers, which would render their CO_2 resistance much higher than that of a biological membrane. Is this also true for a membrane crowded with proteins? This comment summarizes the current status of the debate.