Solitonic Ionic Currents Along Microtubules

Abstract

Microtubules are very important cytoskeletal structures implicated in different cellular activities. We should mention the cell division and traffic of organelles (mitochondria, vesicles and other cargos) by kinesin and dynein motor proteins. Microtubules are also playing important roles in higher neuronal functions including mechanisms of consciousness and memory. We here investigate the circumstances and the conditions enabling microtubules to act as nonlinear electrical transmission lines for ions flow along their cylinders. We established a model in which each tubulin dimmer protein is an electric element with a capacitive, resistive and negative incrementally resistive property due to polyelectrolyte nature of microtubules in cytosol. The particular attention was paid to the role of nano-pores existing between neighboring dimmers within a MT wall which exhibit properties like ionic channels. These nano-pores are candidates to explain some properties of microtubules resembling to unipolar transistors enabling the rectification and amplification of ionic currents.