| 1. |
- Magzoub, Mazin, et al.
(författare)
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N-terminal peptides from unprocessed prion proteins enter cells by macropinocytosis
- 2006
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 348:2, s. 379-385
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Oglęcka, Kamila, et al.
(författare)
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Relevance of the N-terminal NLS-like sequence for membrane interactions of the Prion protein
- 2007
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Ingår i: Biochimica et Biophysica Acta. MR. Reviews on Biomembranes. - : Elsevier BV. - 0304-4157 .- 1879-257X. ; 1778:1, s. 206-213
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the nuclear localization-like sequence KKRPKP, corresponding to the residues 23–28 in the mouse prion protein (mPrP), for its membrane perturbation activity, by comparing effects of two mPrP-derived peptides, corresponding to residues 1–28 (mPrPp(1–28)) and 23–50 (mPrPp(23–50)), respectively. In erythrocytes, mPrPp(1–28) induced 60% haemoglobin leakage after 30 min, whereas mPrPp(23–50) had negligible effects. In calcein-entrapping, large unilamellar vesicles (LUVs), similar results were obtained. Cytotoxicity estimated by lactate dehydrogenase leakage from HeLa cells, was found to be 12% for 50 μM mPrPp(1–28), and 1% for 50 μM mPrPp(23–50). Circular dichroism spectra showed structure induction of mPrPp(1–28) in the presence of POPC:POPG (4:1) and POPC LUVs, while mPrPp(23–50) remained a random coil. Membrane translocation studies on live HeLa cells showed mPrPp(1–28) co-localizing with dextran, suggesting fluid-phase endocytosis, whereas mPrPp(23–50) hardly translocated at all. We conclude that the KKRPKP-sequence is not sufficient to cause membrane perturbation or translocation but needs a hydrophobic counterpart.
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| 3. |
- Oglęcka, Kamila, et al.
(författare)
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Relevance of the N-terminal NLS-like sequence of the prion protein for membrane perturbation effects
- 2008
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002 .- 1878-2434 .- 0005-2736. ; 1778:1, s. 206-213
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the nuclear localization-like sequence KKRPKP, corresponding to the residues 23-28 in the mouse prion protein (mPrP), for its membrane perturbation activity, by comparing effects of two mPrP-derived peptides, corresponding to residues 1-28 (mPrPp(1-28)) and 2350 (rnPrPp(23-50)), respectively. In erythrocytes, mPrPp(1-28) induced similar to 60% haemoglobin leakage after 30 min, whereas mprPp(23-50) had negligible effects. In calcein-entrapping, large unilamellar vesicles (LUVs), similar results were obtained. Cytotoxicity estimated by lactate dehydrogenase leakage from HeLa cells, was found to be similar to 12% for 50 mu M mPrPp(1-28), and similar to 1% for 50 mu M mPrPp(23-50). Circular dichroism spectra showed structure induction of mPrPp(1-28) in the presence of POPC:POPG (4:1) and POPC LUVs, while mprPp(23-50) remained a random coil. Membrane translocation studies on live HeLa cells showed mPrPp(I-28) co-localizing with dextran, suggesting fluid-phase endocytosis, whereas mPrPp(23-50) hardly translocated at all. We conclude that the KKRPKP-sequence is not sufficient to cause membrane perturbation or translocation but needs a hydrophobic counterpart.
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