F-actins and MTs are highly charged cytoskeleton filaments that transmit electric signals, sustain ionic conductance and overcome electrostatic interactions to form higher-order structures (bundles and networks). They carry out biological activities in eukaryotic cellular processes as diverse as directional growth, shape, division, plasticity, and migration. The basis for these filaments to form higher-order structures and enhance their electrical conductivity appears primarily or exclusively dominated by their biochemical and biophysical (polyelectrolyte) properties. However, the underlying principles that support the polyelectrolyte nature of MTs and F-actin and anomalies on their biological functions associated with aging and inheritance conditions are still poorly understood. Thus, an accurate and efficient characterization of the polyelectrolyte properties for cytoskeleton filaments is key to the molecular understanding of electrical signal propagation, bundle and network formation, and their potential nanotechnological applications under different conditions. Current experimental techniques are limited by resolution and sensitivity to obtain information on the molecular mechanisms governing these phenomena.
Recent theoretical multi-scale studies on F-actin in normal conditions using JACFC reveal that a nontrivial balance and competition between electromechanical interactions are responsible for the stability, bundling, and conducting properties of these filaments. Accordingly, molecular or cellular alterations often evident in pathological conditions might break down this balance and competition, leading to cytoskeleton filament dysfunctions such as dysregulated assembly, misleading protein binding, abnormal polymerization stability, and defective electric signal transmission.
