Numerous studies have shown that basic Tat peptide (48-57) internalized non-specifically in cells and localized in the nucleus. Shen, Duanwen Liang, Kexiang Ye, Yunpeng Tetteh, Elizabeth Achilefu, Samuel Preliminary study on the inhibition of nuclear internalization of Tat peptides by conjugation with a receptor-specific peptide and fluorescent dyes Thus, the TAT-fused conjugates could be constructed in more convenient and flexible formats for a wide range of biopharmaceutical applications. These results conclude that the sequence orientation, the spatial structure, and the relative location of the TAT peptide have much less effect on the TAT-mediated protein transduction. Bioinformatic analyses and CD spectroscopic data revealed that the TAT peptide has no defined secondary structure, and conjugating the TAT peptide to the EGFP cargo protein would not alter the native structure and the function of the EGFP protein.
The in vivo study showed that the TAT-EGFP conjugates could be delivered into different organs of mice with different transduction capabilities. Flow cytometric results showed that four TAT-EGFP conjugates were able to traverse HeLa and PC12 cells with almost equal transduction efficiency. These four TAT-EGFP conjugates were incubated with HeLa and PC12 cells for in vitro study as well as injected intraperitoneally to mice for in vivo study. To understand the protein transduction domain (PTD)- mediated protein transduction behavior and to explore its potential in delivering biopharmaceutic drugs, we prepared four TAT-EGFP conjugates: TAT(+)-EGFP, TAT(-)-EGFP, EGFP- TAT(+) and EGFP- TAT(-), where TAT(+) and TAT(-) represent the original and the reversed TAT sequence, respectively. Guo, Qingguo Zhao, Guojie Hao, Fengjin Guan, Yifu Collectively our results suggest that TatC is an insertase for twin-arginine signal peptides and that translocation-proficient signal sequence recognition requires the concerted action of TatC and TatB.Įffects of the TAT peptide orientation and relative location on the protein transduction efficiency. This capacity of TatB is not shared by the homologous TatA protein.
Hence interaction of twin-arginine signal peptides with TatB counteracts their premature cleavage uncoupled from translocation. In the absence of TatB, this can lead to the removal of the signal sequence even from a translocation-incompetent substrate. Here we show that beyond recognition, TatC mediates the transmembrane insertion of a twin-arginine signal sequence, thereby translocating the signal sequence cleavage site across the bilayer. TatC was previously shown to be involved in recognizing twin-arginine signal peptides.
Many Tat translocases comprise the three membrane proteins TatA, TatB and TatC. The twin-arginine translocation ( Tat) pathway of bacteria and plant chloroplasts mediates the transmembrane transport of folded proteins, which harbour signal sequences with a conserved twin-arginine motif. Transmembrane insertion of twin-arginine signal peptides is driven by TatC and regulated by TatB. Collectively our results suggest that TatC is an insertase for twin-arginine signal peptides and that translocation-proficient signal sequence recognition requires the concerted action of TatC and TatB.
Transmembrane insertion of twin-arginine signal peptides is driven by TatC and regulated by TatBįröbel, Julia Rose, Patrick Lausberg, Frank Blümmel, Anne-Sophie Freudl, Roland Müller, Matthias