title: Receptor/transporter-independent targeting of functional peptides across the plasma membrane.
abstract: Targeting of peptides, proteins, and other functional cargo into living cells is contingent upon efficient transport across the plasma membrane barrier. We have harnessed the signal sequence hydrophobic region (SSHR) to deliver functional cargoes to cultured cells and to experimental animals. We now report evidence that two chirally distinct forms of SSHR composed of all l or all d amino acids showed similar membrane-translocating activity as assessed by confocal microscopy, flow cytometry, and direct fluorescence measurement. An attached nuclear localization sequence ferried by the SSHR enantiomers displayed similar intracellular function by inhibiting inducible nuclear import of transcription factor nuclear factor kappa B and suppressing nuclear factor kappa B-dependent gene expression of cytokines. A nuclear localization sequence comprised of a positively charged cluster of amino acids was rapidly translocated by SSHR enantiomers to the interior of unilamellar phospholipid vesicles. These findings indicate that the SSHR translocates functional peptides directly through the plasma membrane phospholipid bilayer without involving chirally specific receptor/transporter mechanisms. This mechanism of SSHR translocation is suitable for facile delivery of biologically active peptides for cell-based and animal-based functional proteomic studies.
authors.affiliation: Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2363, USA.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Veach
authors.forename: Danya
authors.initials: D
authors.lastname: Liu
authors.forename: Shan
authors.initials: S
authors.lastname: Yao
authors.forename: Yiliu
authors.initials: Y
authors.lastname: Chen
authors.forename: Xue Yan
authors.initials: XY
authors.lastname: Liu
authors.forename: Sheila
authors.initials: S
authors.lastname: Downs
authors.forename: Jacek
authors.initials: J
authors.lastname: Hawiger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D005434:Flow Cytometry; D008051:Lipid Bilayers; D051379:Mice; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D008051:Lipid Bilayers; D010455:Peptides; D010743:Phospholipids