Arginine-rich peptides destabilize the plasma membrane, consistent with a pore formation translocation mechanism of cell penetrating peptides

TL;DR

This study combines molecular dynamics simulations and experimental measurements to demonstrate that arginine-rich peptides destabilize membranes by forming transient pores, supporting a pore formation translocation mechanism for cell-penetrating peptides.

Contribution

The paper provides evidence that arginine-rich peptides induce transient pore formation in membranes, elucidating their translocation mechanism through combined simulation and experimental approaches.

Findings

Arg-9 peptides induce ionic currents across lipid bilayers.

Arg-9 peptides create transient pores in cell membranes.

Membrane destabilization by Arg-9 supports pore formation translocation mechanism.

Abstract

Recent molecular dynamics simulations (Herce and Garcia, PNAS, 104: 20805 (2007)) have suggested that the arginine-rich HIV Tat peptides might be able to translocate by destabilizing and inducing transient pores in phospholipid bilayers. In this pathway for peptide translocation, arginine 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, despite being charged and highly hydrophilic. Here we present a molecular dynamics simulation of a peptide composed of nine arginines (Arg-9) that shows that this peptide follows the same translocation pathway previously found for the Tat peptide. We test this hypothesis experimentally 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 freshly isolated from the umbilical artery. Our results suggest that the mechanism of action of Arg-9 peptide involves the creation of transient pores in lipid bilayers and cell membranes.