Emiko Okamura - Glycosaminoglycan Binding and Non-Endocytic Membrane Translocation of Cell-Permeable Octaarginine Monitored by Real-Time In-Cell NMR Spectroscopy

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      Publication Details (including relevant citation   information):

      Yuki Takechi-Haraya, Kenzo Aki, Yumi Tohyama, Yuichi Harano, Toru   Kawakami, Hiroyuki Saito, Emiko Okamura. Pharmaceuticals  2017, 10, 42; doi:10.3390/ph10020042


          Glycosaminoglycans (GAGs) which are covalently linked membrane   proteins at the cell surface have recently been suggested to   involve in not only endocytic cellular uptake but also   non-endocytic direct cell membrane translocation of arginine-rich   cell penetrating peptides (CPPs). However, in-situ comprehensive   observation and the quantitative analysis of the direct membrane   translocation processes are challenging, and the mechanism   therefore remains still unsolved. In this work, real time in-cell   NMR spectroscopy was applied to investigate the direct membrane   translocation of octaarginine (R8) into living cells. By   introducing 4-trifluoromethyl-L-phenylalanine to N terminus of   R8, the non-endocytic membrane translocation of   19F-labeled R8 into a human myeloid leukemia cell line   was observed at 4 °C with a time resolution of minute-order.   19F NMR successfully detected real time R8   translocation: the binding to anionic GAGs at the cell surface,   followed by the penetration into the cell membrane, and the entry   into cytosol across the membrane. The NMR concentration analysis   enabled to quantify how much of R8 was staying in the respective   translocation processes with time in situ. Taken together, our   in-cell NMR results provide the physicochemical rationale for   spontaneous penetration of CPPs in cell membranes.

      Address (URL): http://www.mdpi.com/1424-8247/10/2/42/htm