Novel Cell-Penetrating Peptides Overcome Endosomal Escape and Deliver Protein Cargos into the Cell

Over the last decade a number of peptides that are rapidly internalized by mammalian cells have been discovered or designed. Cell-penetrating peptides (CPPs) are capable of mediating penetration of the plasma membrane, allowing delivery of macromolecular cargoes to the cell interior. We have developed a novel CPP-adaptor protein technology that allows any user-defined cargo delivery and release into the cytoplasm. Our hypothesis is that a CPP-adaptor with a moiety allowing high-affinity but reversible non-covalent cargo binding would lead to more efficient penetration and release than current CPP delivery strategies. Delivery of proteins to the interiors of cells has many applications. In addition to detecting and mapping the location of the components of living cells with fluorescent tags in real time, the availability of our system will enable the manipulation of signaling pathways and gene expression by allowing the introduction of components, e.g. constitutively active kinases, repressors or enhancers...