title: Efficient Delivery of Structurally Diverse Protein Cargo into Mammalian Cells by a Bacterial Toxin.
abstract: Platforms enabling targeted delivery of proteins into cells are needed to fully realize the potential of protein-based therapeutics with intracellular sites-of-action. Bacterial toxins are attractive systems to consider as templates for designing protein transduction systems as they naturally bind and enter specific cells with high efficiency. Here we investigated the capacity of diphtheria toxin to function as an intracellular protein delivery vector. We report that diphtheria toxin delivers an impressive array of passenger proteins spanning a range of sizes, structures, and stabilities into cells in a manner that indicates that they are "invisible" to the translocation machinery. Further, we show that α-amylase delivered into cells by a detoxified diphtheria toxin chimera digests intracellular glycogen in live cells, providing evidence that delivered cargo is folded, active, and abundant. The efficiency and versatility of diphtheria toxin over existing systems open numerous possibilities for intracellular delivery of bioactive proteins.
authors.forename: Anick
authors.initials: A
authors.lastname: Auger
authors.affiliation: ‡Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
authors.forename: Minyoung
authors.initials: M
authors.lastname: Park
authors.forename: Felix
authors.initials: F
authors.lastname: Nitschke
authors.forename: Lori M
authors.initials: LM
authors.lastname: Minassian
authors.forename: Greg L
authors.initials: GL
authors.lastname: Beilhartz
authors.affiliation: ∥Department of Paediatrics, University of Toronto, Toronto, ON, Canada.
authors.forename: Berge A
authors.initials: BA
authors.lastname: Minassian
authors.affiliation: ‡Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
authors.forename: Roman A
authors.initials: RA
authors.lastname: Melnyk
mesh_terms: D002152:Calorimetry, Differential Scanning; D004167:Diphtheria Toxin / Q000378:metabolism*; D016503:Drug Delivery Systems; D006003:Glycogen / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D010446:Peptide Fragments / Q000378:metabolism*; D017510:Protein Folding; D000516:alpha-Amylases / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004167:Diphtheria Toxin; D010446:Peptide Fragments; D006003:Glycogen; D000516:alpha-Amylases
keywords: diphtheria toxin; intracellular protein delivery; toxin translocation