Interaction Between F-Actin and Negatively Charged Lipids Membrane

Actin is a ubiquitous cytoskeletal protein involved in many fundamental cellular processes. In a cell, actin generally performs its functions in its polymerized form (F-actin). It is well known that the interior membrane of the natural membranes contains a large amount of negatively charged lipids, so the study of the interaction between F-actin and negatively charged lipids would bring some insight on the interaction between the cytoskeleton and the cell membrane in vivo. The interaction of F-actin and negatively charged lipids membrane has been investigated by surface plasmon resonance and electrochemical impedance spectroscopy. The result shows that F-actin can interact with the negatively charged lipids membrane directly without any intermediate linker protein. Ca2+ can effectively promote this interaction, indicating that in this case, the divalent cations played an important role. High concentrations of KCl will inhibit this interaction significantly, indicating that the interaction between F-actin and negatively charged lipid membrane is mainly dominated by electrostatic interactions, although other forces also involved. The results indicate that two mechanisms of the interaction between F-actin and the lipids membrane may exist: direct interaction with lipids and interaction through other membrane protein.