Intrinsic potential of cell membranes: opposite effects of lipid transmembrane asymmetry and asymmetric salt ion distribution.
Using atomic-scale molecular dynamics simulations, we consider the intrinsic cell membrane potential that is found to originate from a subtle interplay between lipid transmembrane asymmetry and the asymmetric distribution of monovalent salt ions on the two sides of the cell membrane. It turns out that both the asymmetric distribution of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) lipids across a membrane and the asymmetric distribution of NaCl and KCl induce nonzero drops in the transmembrane potential. However, these potential drops are opposite in sign. As the PC leaflet faces a NaCl saline solution and the PE leaflet is exposed to KCl, the outcome is that the effects of asymmetric lipid and salt ion distributions essentially cancel one another almost completely. Overall, our study highlights the complex nature of the intrinsic potential of cell membranes under physiological conditions.
Gurtovenko
Andrey A
AA
Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, V.O., St. Petersburg 199004, Russia.
Vattulainen
Ilpo
I
D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D020404:Glycerophospholipids / Q000737:chemistry / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects*; D008958:Models, Molecular; D008968:Molecular Conformation; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism; D010714:Phosphatidylethanolamines / Q000737:chemistry / Q000378:metabolism; D011189:Potassium Chloride / Q000378:metabolism* / Q000494:pharmacology; D011312:Pressure; D012965:Sodium Chloride / Q000378:metabolism* / Q000494:pharmacology; D055672:Static Electricity; D013696:Temperature; D013997:Time Factors
D020404:Glycerophospholipids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; C057561:1-palmitoyl-2-oleoylphosphatidylethanolamine; D012965:Sodium Chloride; D011189:Potassium Chloride; C028694:1-palmitoyl-2-oleoylphosphatidylcholine