Voltage-induced membrane movement

Citation
Pc. Zhang et al., Voltage-induced membrane movement, NATURE, 413(6854), 2001, pp. 428-432
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary,Multidisciplinary,Multidisciplinary
Journal title
NATURE
ISSN journal
0028-0836 → ACNP
Volume
413
Issue
6854
Year of publication
2001
Pages
428 - 432
Database
ISI
SICI code
0028-0836(20010927)413:6854<428:VMM>2.0.ZU;2-W
Abstract
Thermodynamics predicts that transmembrane voltage modulates membrane tensi on(1) and that this will cause movement. The magnitude and polarity of move ment is governed by cell stiffness and surface potentials. Here we confirm these predictions using the atomic force microscope to dynamically follow t he movement of voltage-clamped HEK293 cells(2) in different ionic-strength solutions. In normal saline, depolarization caused an outward movement, and at low ionic strength an inward movement. The amplitude was proportional t o voltage (about 1 nm per 100 mV) and increased with indentation depth. A s imple physical model of the membrane and tip provided an estimate of the ex ternal and internal surface charge densities (-5 x10(-3) C m(-2) and -18x10 (-3) C m(-2), respectively). Salicylate (a negative amphiphile(3)) inhibite d electromotility by increasing the external charge density by -15x10(-3) C m(-2). As salicylate blocks electromotility in cochlear outer hair cells a t the same concentration(4,5), the role of prestin as a motor protein(6) ma y need to be reassessed.