INTERACTION OF ACTIN WITH POSITIVELY CHARGED PHOSPHOLIPIDS - A MONOLAYER STUDY

The interactions of actin, a negatively charged cytoskeletal protein, with lipids have been studied by the monolayer technique. The lipids (either pure phosphatidylcholine or incorporating 10%, 30% or 50% of a positively charged surfactant, stearylamine) were spread at the air/water interface and actin was allowed to interact with the monolayer after injection in the subphase. The results show that at a given surface pressure, increasing the density of positive charges in the lipid monolayer causes a significant increase in the intercalation of the actin within the lipid molecules, thereby indicating that the adsorption of actin is facilitated by electrostatic interactions. However, this intercalation is only possible up to a critical surface pressure above which actin does not penetrate the lipid surface. © 1993 Academic Press, Inc.