title: Plasma membrane translocation of a protein needle based on a triple-stranded β-helix motif.
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.
authors.affiliation: Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan. kitagawa@icems.kyoto-u.ac.jp tueno@bio.titech.ac.jp.
authors.forename: Nusrat J M
authors.initials: NJ
authors.lastname: Sanghamitra
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inaba
authors.forename: Fumio
authors.initials: F
authors.lastname: Arisaka
authors.forename: Dan
authors.initials: D
authors.lastname: Ohtan Wang
authors.forename: Shuji
authors.initials: S
authors.lastname: Kanamaru
authors.forename: Susumu
authors.initials: S
authors.lastname: Kitagawa
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ueno
mesh_terms: D020816:Amino Acid Motifs; D017122:Bacteriophage T4 / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008564:Membrane Potentials; D008958:Models, Molecular; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D011506:Proteins; D014764:Viral Proteins