Temperature-, concentration- and cholesterol-dependent translocation of L- and D-octa-arginine across the plasma and nuclear membrane of CD34+ leukaemia cells

• DOI: 10.1042/bj20061808
• Publication Date: 2007-03-26T15:15:17Z
• Authors: Marjan M. Fretz; Neal A. Penning; Saly Al-Taei; Shiroh Futaki; Toshihide Takeuchi; Ikuhiko Nakase; Gert Storm; Arwyn T. Jones
• Keywords: Cell-penetrating peptide; Internalization

Delineating the mechanisms by which cell-penetrating peptides, such as HIV-Tat peptide, oligoarginines and penetratin, gain access to cells has recently received intense scrutiny. Heightened interest in these entities stems from their ability enhance cellular delivery of associated macromolecules, genes proteins, suggesting that they may have widespread applications drug-delivery vectors. Proposed uptake include energy-independent plasma membrane translocation energy-dependent vesicular internalization through endocytic pathways. In present study, we investigated effects temperature, peptide concentration cholesterol levels on a model L-octa-arginine (L-R8) its D-enantiomer (D-R8) CD34+ leukaemia cells. We found that, at 4–12 °C, L-R8 uniformly labels cytoplasm nucleus, but incubated with D-R8 there is additional labelling nucleolus still prominent 30 °C incubations. At temperatures between 12 peptides are also localized vesicles consequently appear only labelled structures 37 °C. Small increases extracellular incubations result dramatic increase fraction cytosol promoted binding nucleolus. Enhanced cytosol, nucleus was achieved extraction methyl-β-cyclodextrin. The data argue for two, temperature-dependent, mechanism existence threshold when exceeded promotes direct across membrane.