Interaction Between F-Actin and Negatively Charged Lipids Membrane

Charge-dependent interactions of monomeric and filamentous actin with lipid bilayers

“…Other in vitro experiments have shown, however, that actin can in fact interact with neutral or negatively charged bilayers (9,10,18). This contradiction may be reconciled by considering the presence of divalent ions, calcium or magnesium, in the buffer.…”

“…For all of these purposes, actin has to interact with lipid membranes, and a number of in vitro studies have tried to elucidate the nature of actin-membrane interactions (8)(9)(10). One central outcome of these studies is the importance of the presence of charged lipids for the ability of actin filaments to adsorb directly to the membrane: F-actin generally does not adsorb to bilayers consisting only of neutral lipids, or partially of negatively charged lipids (10)(11)(12), consistent with the overall negative charge of actin filaments (13). In contrast, positively charged lipid mono-and bilayers are not only able to adsorb the filaments (8,(14)(15)(16) but can even catalyze the formation of F-actin (8,15) and form stacked hierarchical structures (17).…”

“…This contradiction may be reconciled by considering the presence of divalent ions, calcium or magnesium, in the buffer. There is strong experimental evidence that diva-lent ions can reverse the adsorption properties of lipid bilayers (9,10), which is reminiscent of divalent ions acting as a molecular glue that allows F-actin to form bundles (19)(20)(21)(22). A systematic evaluation of actin-membrane binding with respect to both bilayer composition and ion concentration is so far lacking.…”