Arginine-Rich Peptides Destabilize the Plasma Membrane, Consistent with a Pore Formation Translocation Mechanism of Cell-Penetrating Peptides

Abstract

Recent molecular-dynamics simulations have suggested that the arginine-rich HIV Tat peptides translocate by destabilizing and inducing transient pores in phospholipid bilayers. In this pathway for peptide translocation, Arg residues play a fundamental role not only in the binding of the peptide to the surface of the membrane, but also in the destabilization and nucleation of transient pores across the bilayer. Here we present a molecular-dynamics simulation of a peptide composed of nine Args (Arg-9) that shows that this peptide follows the same translocation pathway previously found for the Tat peptide. We test experimentally the hypothesis that transient pores open by measuring ionic currents across phospholipid bilayers and cell membranes through the pores induced by Arg-9 peptides. We find that Arg-9 peptides, in the presence of an electrostatic potential gradient, induce ionic currents across planar phospholipid bilayers, as well as in cultured osteosarcoma cells and human smooth muscle cells. Our results suggest that the mechanism of action of Arg-9 peptides involves the creation of transient pores in lipid bilayers and cell membranes.

Structure and dynamics of cationic membrane peptides and proteins: Insights from solid‐state NMR

“…An earlier inverse micelle model 116 can be ruled out by the lack of isotropic signals in static 31 P NMR spectra. 49 A membrane-crossing mechanism for CPPs was supported by MD simulations 8,117 and by the solid-state NMR data summarized here. The CPP interaction with lipids is unique in many ways among membrane peptides.…”

Pathogenic Serum Amyloid A 1.1 Shows a Long Oligomer-rich Fibrillation Lag Phase Contrary to the Highly Amyloidogenic Non-pathogenic SAA2.2

“…Planar Lipid Bilayer Experiments-Asolectin (Avanti Polar Lipids Inc.) bilayers were made by dissolving in n-decane at a concentration of 200 mg/ml (13,14) and formed over a polystyrene cup with a 100-m-diameter aperture and inserted into a thermally conductive chamber. The cup and the chamber were filled with 1 ml of 20 mM HEPES buffer (100 mM KCl, pH 7.4).…”

Atomistic Molecular Simulations Suggest a Kinetic Model for Membrane Translocation by Arginine-Rich Peptides

“…7,8 Another commonly posited model is that ARCPPs are able to permeate cell membranes by facilitating membrane pore formation. 4,9,10 That is, it is believed that ARCPPs are able to significantly lower the thermodynamic cost of membrane pore formation. However, there is still no generally accepted explanation as to how this is achieved by this class of peptide and not others, such as oligolysines.…”