Relevance of the N-terminal NLS-like sequence for membrane interactions of the Prion protein

• 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.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Andra medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Other Basic Medicine (hsv//eng)

Keyword

Prion protein

Membrane translocation

Calcein leakage

Endosomal escape

NLS-like sequence

Haemoglobin leakage

Chemistry

Kemi

Publication and Content Type

ref (subject category)

art (subject category)