title: N-terminal peptides from unprocessed prion proteins enter cells by macropinocytosis.
abstract: A peptide derived from the N-terminus of the unprocessed bovine prion protein (bPrPp), incorporating the hydrophobic signal sequence (residues 1-24) and a basic domain (KKRPKP, residues 25-30), internalizes into mammalian cells, even when coupled to a sizeable cargo, and therefore functions as a cell-penetrating peptide (CPP). Confocal microscopy and co-localization studies indicate that the internalization of bPrPp is mainly through macropinocytosis, a fluid-phase endocytosis process, initiated by binding to cell-surface proteoglycans. Electron microscopy studies show internalized bPrPp-DNA-gold complexes residing in endosomal vesicles. bPrPp induces expression of a complexed luciferase-encoding DNA plasmid, demonstrating the peptide's ability to transport the cargo across the endosomal membrane and into the cytosol and nucleus. The novel CPP activity of the unprocessed N-terminal domain of PrP could be important for the retrotranslocation of partly processed PrP and for PrP trafficking inside or between cells, with implications for the infectivity associated with prion diseases.
authors.affiliation: Department of Biochemistry and Biophysics, Stockholm University, Sweden.
authors.forename: Mazin
authors.initials: M
authors.lastname: Magzoub
authors.forename: Staffan
authors.initials: S
authors.lastname: Sandgren
authors.forename: Pontus
authors.initials: P
authors.lastname: Lundberg
authors.forename: Kamila
authors.initials: K
authors.lastname: Oglecka
authors.forename: Johanna
authors.initials: J
authors.lastname: Lilja
authors.forename: Anders
authors.initials: A
authors.lastname: Wittrup
authors.forename: L E
authors.initials: LE
authors.lastname: Göran Eriksson
authors.forename: Ulo
authors.initials: U
authors.lastname: Langel
authors.forename: Mattias
authors.initials: M
authors.lastname: Belting
authors.forename: Astrid
authors.initials: A
authors.lastname: Gräslund
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D016466:CHO Cells; D002417:Cattle; D006224:Cricetinae; D003412:Cricetulus; D015638:Cytochalasin D / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism*; D010873:Pinocytosis / Q000502:physiology*; D011328:Prions / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D010446:Peptide Fragments; D011328:Prions; D015638:Cytochalasin D; D000077191:Wortmannin