INTERACTION BETWEEN FILAMENTOUS ACTIN AND LIPID BILAYER CAUSES THE INCREASE OF
SYRINGOMYCIN E CHANNEL-FORMING ACTIVITY
A. N. Bessonov,1 Ph. A. Gurnev,1. M. Kuznetsova,1
J. Takemoto,2
K. K. Turoverov,1 V. V. Malev,1, 3 L. V. Schagina1 *
1 Institute of Cytology RAS, St. Petersburg, Russia, 2 Utah State University, Logan,
Utah, USA, and
3 St. Petersburg State University, St. Petersburg, Russia;
* e-mail: lvschag@mail.cytspb.rssi.ru
The effect of filamentous (F) actin on the channel-forming activity of syringomycin E (SRE) in negatively charged and
uncharged bilayer lipid membranes (BLM) was studied. F-actin did not affect the membrane conductance in the absence of SRE.
No changes in SRE-induced membrane conductance were observed when the above agents were added to the same side of BLM.
However, the opposite side addition of F-actin and SRE provokes a multiple increase in membrane conductance. The similar voltage
dependence of membrane conductance, equal values of single channel conductance and the effective gating charge of the channels
upon F-actin action suggests that the actin-dependent increase in BLM conductance may result from an increase in the number of
opened SRE-channels. BLM conductance kinetics depends on the sequence of SRE and F-actin addition, suggesting that actin-dependent
rise of conductance may be induced by BLM structural changes that follow F-actin adsorption. F-actin exerted similar effect on membrane
conductance of both negatively charged and uncharged bi-layers, as well as on conductance of BLM with high ionic strength bathing
solution, suggesting the major role for hydrophobic interactions in F-actin adsorption on lipid bilayer.
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