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Cell transduction pathways of transportans
Kärt Padari1, Pille Säälik, Mats Hansen
1Estonian Biocenter, 23 Riia Street, 51010 Tartu, Estonia.
Bioconjugate Chemistry
|November 17, 2005
Summary
Cell-penetrating peptides (CPPs) like transportan facilitate protein entry into cells, primarily via endocytic vesicles. Some complexes escape these vesicles, entering the cytoplasm, with translocation being temperature-dependent.
Area of Science:
- Cell Biology
- Biochemistry
- Peptide Science
Background:
- Cell-penetrating peptides (CPPs) are crucial for delivering cargo into cells.
- Peptide sequence and charge are key factors influencing CPP internalization.
- Research focuses on designing efficient CPPs and understanding their entry mechanisms.
Purpose of the Study:
- To map the cell surface interactions and intracellular trafficking of transportan and TP10.
- To investigate the mechanism of cell entry for peptide-protein complexes.
- To analyze the role of CPPs in delivering protein cargo.
Main Methods:
- Transmission electron microscopy (TEM) to visualize vesicle morphology.
- Confocal laser scanning fluorescence microscopy to track cargo.
- Utilizing fluorescently labeled avidin/streptavidin-gold conjugates with peptides.
Main Results:
- Transportan and TP10 complexes enter HeLa and Bowes cells mainly via endocytic vesicles (macropinosomes and smaller vesicles).
- Complexes translocate to perinuclear regions and lysosomes, with some escaping into the cytoplasm.
- Cell translocation is temperature-dependent, inhibited at low temperatures (4-10°C).
Conclusions:
- Transportan and TP10 mediate protein cargo entry through diverse endocytic pathways.
- Evidence suggests endosomal escape and direct cytoplasmic entry.
- Temperature significantly influences the cell translocation efficiency of these CPP-protein complexes.