Voltage-induced morphological modifications in oocyte membranes containing exogenous K+ channels studied by electrochemical scanning force microscopy.
We report on a novel use of electrochemical scanning force microscopy (SFM) for the investigation of morphological modifications occurring in plasma membranes containing voltage-gated ion channels, on membrane potential variation. Membrane patches of Xenopus laevis oocytes microinjected with exogenous KAT1 cRNA, deposited by a stripping method at the surface of a derivatized gold film in inside-out configuration, have been imaged by SFM in an electrochemical cell. A potentiostat was used to maintain a desired potential drop across the membrane. Performing imaging at potential values corresponding to open (-120 mV) and closed (+20 mV) states for KAT1, morphological differences in localized sample zones were observed. Particularly, cross-shaped features involving a significant membrane portion appear around putative channel locations. The reported approach constitutes the first demonstration of an SPM-based experimental technique suitable to investigate the rearrangements occurring to the plasma membrane containing voltage-gated channels on transmembrane potential variation.
National Research Council - National Institute for the Physics of Matter, Center nanoStructures and bioSystems at Surfaces - S3 Modena, Italy.
Andrea
A
Alessandrini
Paola
P
Gavazzo
Cristiana
C
Picco
Paolo
P
Facci
D000818:Animals; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D004553:Electric Conductivity; D004563:Electrochemistry; D015640:Ion Channel Gating; D018625:Microscopy, Atomic Force / Q000379:methods*; D009865:Oocytes / Q000378:metabolism / Q000648:ultrastructure; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism*; D024642:Potassium Channels, Voltage-Gated; D014982:Xenopus laevis
D029681:Arabidopsis Proteins; C501210:KAT1 protein, Arabidopsis; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated