Plasma membrane translocation of a protein needle based on a triple-stranded β-helix motif

Mol Biosyst. 2014 Oct;10(10):2677-83. doi: 10.1039/c4mb00293h.

Abstract

Plasma membrane translocation is challenging due to the barrier of the cell membrane. Contrary to the synthetic cell-penetrating materials, tailed bacteriophages use cell-puncturing protein needles to puncture the cell membranes as an initial step of the DNA injection process. Cell-puncturing protein needles are thought to remain functional in the native phages. In this paper, we found that a bacteriophage T4 derived protein needle of 16 nm length spontaneously translocates through the living cell membrane. The β-helical protein needle (β-PN) internalizes into human red blood cells that lack endocytic machinery. By comparing the cellular uptake of β-PNs with modified surface charge, it is shown that the uptake efficiency is maximum when it has a negative charge corresponding to a zeta potential value of -16 mV. In HeLa cells, uptake of β-PN incorporates endocytosis independent mechanisms with partial macropinocytosis dependence. The endocytosis dependence of the uptake increases when the surface charges of β-PNs are modified to positive or negative. Thus, these results suggest that natural DNA injecting machinery can serve as an inspiration to design new class of cell-penetrating materials with a tailored mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs*
  • Bacteriophage T4 / metabolism
  • Cell Membrane / metabolism*
  • Erythrocytes / metabolism
  • HeLa Cells
  • Humans
  • Membrane Potentials
  • Models, Molecular
  • Protein Conformation
  • Protein Interaction Domains and Motifs*
  • Protein Transport
  • Proteins / chemistry*
  • Proteins / metabolism*
  • Viral Proteins / genetics
  • Viral Proteins / metabolism

Substances

  • Proteins
  • Viral Proteins