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Shlyonsky VG, Markin VS, Andreeva I, Pedersen SE,
Simon SA, Benos DJ, Ismailov II.
Biochim Biophys Acta. 2006 Nov;1758(11):1723-31.
Role of membrane curvature in mechanoelectrical
transduction: ion carriers nonactin and valinomycin sense
changes in integral bending energy.
Department of Physiology and Biophysics, University
of Alabama at Birmingham, Birmingham, AL 35294, USA.
We describe the phenomenon of mechanoelectrical
transduction in macroscopic lipid bilayer membranes modified by
two cation-selective ionophores, valinomycin and nonactin. We
found that bulging these membranes, while maintaining the
membrane tension constant, produced a marked supralinear
increase in specific carrier-mediated conductance. Analyses of
the mechanisms involved in mechanoelectrical transduction
induced by the imposition of a hydrostatic pressure gradient or
by an amphipathic compound chlorpromazine reveal similar changes
in the charge carrier motility and carrier reaction rates at the
interface(s). Furthermore, the relative change in membrane
conductance was independent of membrane diameter, but was
directly proportional to the square of membrane curvature, thus
relating the observed phenomena to the bilayer bending energy.
Extrapolated to biological membranes, these findings indicate
that ion transport in cells can be influenced simply by changing
shape of the membrane, without a change in membrane tension.
PMID: 17069752 |
