Cationic Peptides and Cell Penetration

Controversy surrounds how certain cationic peptides enter the cell, as described by The Scientist. The so-called cell-penetrating peptides (CPPs) reportedly appeared to cross plasma membranes directly, which was seen as surprising because the molecule is not the kind of molecule one often sees passing through hydrophobic membranes. Kamran Melikov and his lab team, headed by Leonid Chernomordik (U.S. National Institute of Child Health and Human Development), along with a CNRS group at the University of Montpellier headed by Bernard Lebleu, reportedly showed that uptake was largely due to endocytosis, they suggested, which means any drug conjugated to such a peptide would still be segregated from the cytoplasm. Researchers including Melikov's group continue to investigate how a CPP might escape the endosome to serve as effective drug carrier.