The prion protein family member Shadoo induces spontaneous ionic currents in cultured cells.
Some mutant forms of the cellular prion protein (PrPC) carrying artificial deletions or point mutations associated with familial human prion diseases are capable of inducing spontaneous ionic currents across the cell membrane, conferring hypersensitivity to certain antibiotics to a wide range of cultured cells and primary cerebellar granular neurons (CGNs). These effects are abrogated when the wild type (WT) form is co-expressed, suggesting that they might be related to a physiological activity of PrPC. Interestingly, the prion protein family member Shadoo (Sho) makes cells hypersensitive to the same antibiotics as mutant PrP-s, an effect that is diminished by the co-expression of WT-PrP. Here, we report that Sho engages in another mutant PrP-like activity: it spontaneously induces large ionic currents in cultured SH-SY5Y cells, as detected by whole-cell patch clamping. These currents are also decreased by the co-expression of WT-PrP. Furthermore, deletion of the N-terminal (RXXX)8motif of Sho, mutation of the eight arginine residues of this motif to glutamines, or replacement of the hydrophobic domain by that of PrP, also diminish Sho-induced ionic currents. Our results suggest that the channel activity that is also characteristic to some pathogenic PrP mutants may be linked to a physiological function of Sho.
Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary.|Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
Antal
A
Nyeste
Dulbecco Telethon Laboratory of Prions and Amyloids, Center for Integrative Biology (CIBIO), University of Trento, 38123 Trento, ITALY.
Claudia
C
Stincardini
Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
Petra
P
Bencsura
Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milano, ITALY.
Milica
M
Cerovic
Dulbecco Telethon Laboratory of Prions and Amyloids, Center for Integrative Biology (CIBIO), University of Trento, 38123 Trento, ITALY.|Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, 20156 Milano, ITALY.
Emiliano
E
Biasini
Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary.|Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
Ervin
E
Welker
D000200:Action Potentials / Q000502:physiology*; D020816:Amino Acid Motifs; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D058851:GPI-Linked Proteins / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D016296:Mutagenesis; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains
D000900:Anti-Bacterial Agents; D058851:GPI-Linked Proteins; D009419:Nerve Tissue Proteins; C478971:SPRN protein, human