Polycationic macromolecules and cationic peptides acting as PTDs (protein transduction domains) and CPPs (cell-penetrating peptides) represent important classes of agents used for the import and delivery of a wide range of molecular cargoes into cells. Their entry into cells is typically initiated through interaction with cell-surface HS (heparan sulfate) molecules via electrostatic interactions, followed by endocytosis of the resulting complexes. However, the endocytic mechanism employed (clathrin-mediated endocytosis, caveolar uptake or macropinocytosis), defining the migration of these peptides into cells, depends on parameters such as the nature of the cationic agent itself and complex formation with cargo, as well as the nature and distribution of proteoglycans expressed on the cell surface. Moreover, a survey of the literature suggests that endocytic pathways should not be considered as mutually exclusive, as more than one entry mechanism may be operational for a given cationic complex in a particular cell type. Specifically, the observed import may best be explained by the distribution and uptake of cell-surface HSPGs (heparan sulfate proteoglycans), such as syndecans and glypicans, which have been shown to mediate the uptake of many ligands besides cationic polymers. A brief overview of the roles of HSPGs in ligand internalization is presented, as well as mechanistic hypotheses based on the known properties of these cell-surface markers. The identification and investigation of interactions made by glycosaminoglycans and core proteins of HSPGs with PTDs and cationic polymers will be crucial in defining their uptake by cells.
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August 2007
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Conference Article|
July 20 2007
Cell-surface proteoglycans as molecular portals for cationic peptide and polymer entry into cells
G.M.K. Poon;
G.M.K. Poon
1Division of Cancer Genomics and Proteomics, Ontario Cancer Institute, University Health Network, Ontario, Canada M5G 2M9
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J. Gariépy
J. Gariépy
1
1Division of Cancer Genomics and Proteomics, Ontario Cancer Institute, University Health Network, Ontario, Canada M5G 2M9
1To whom correspondence should be addressed (email gariepy@uhnres.utoronto.ca).
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Publisher: Portland Press Ltd
Received:
April 23 2007
Online ISSN: 1470-8752
Print ISSN: 0300-5127
© The Authors Journal compilation © 2007 Biochemical Society
2007
Biochem Soc Trans (2007) 35 (4): 788–793.
Article history
Received:
April 23 2007
Citation
G.M.K. Poon, J. Gariépy; Cell-surface proteoglycans as molecular portals for cationic peptide and polymer entry into cells. Biochem Soc Trans 1 August 2007; 35 (4): 788–793. doi: https://doi.org/10.1042/BST0350788
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