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Prion protein/protein interactions: fusion with yeast Sup35p‐NM modulates cytosolic PrP aggregation in mammalian cells
Author(s) -
Krammer Carmen,
Suhre Michael H.,
Kremmer Elisabeth,
Diemer Claudia,
Hess Simone,
Schätzl Hermann M.,
Scheibel Thomas,
Vorberg Ina
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.07-8733com
Subject(s) - cytosol , saccharomyces cerevisiae , protein aggregation , microbiology and biotechnology , chemistry , fusion protein , yeast , biophysics , protein folding , gene isoform , fungal prion , plasma protein binding , biochemistry , recombinant dna , biology , gene , enzyme
In mammalian prion diseases, an abnormally folded, aggregated form of the prion protein (PrP Sc ) appears to catalyze a conformational switch of its cellular isoform (PrP C ) to an aggregated state. A similar prion‐like phenomenon has been reported for the Saccharomyces cerevisiae translation termination factor Sup35p that can adopt a self‐propagating conformation. We have compared aggregation propensities of chimeric proteins derived from the Sup35p prion domain NM and PrP in vitro and in the cytosol of mammalian cells. Sup35p‐NM and PrP displayed strikingly different aggregation behaviors when expressed in mammalian cells, with NM remaining soluble and cytosolic PrP spontaneously aggregating due to the globular domain of PrP. When fused to PrP 90–230 , Sup35p‐M exhibited an inhibitory effect for nucleation but increased aggregate growth, potentially by facilitating recruitment of newly synthesized chimeric proteins into the growing aggregates. This effect, however, could, to some extent, be counteracted by the prion‐forming region Sup35p‐N, thereby increasing aggregate frequency. Interestingly, a lowered nucleation rate was also observed in the presence of the amino‐terminal region of PrP, suggesting that Sup35p‐M and PrP 23–90 share some biological function in prion protein assembly. Our results provide new insights into prion protein aggregation behaviors, demonstrating the impact of dynamic interactions between prion domains and suggesting that aggregation of yeast and mammalian prion proteins is strongly influenced by yet unidentified cellular conditions or factors.—Krammer C., Suhre, M. H., Kremmer, E., Diemer, C., Hess, S., Schatzl, H. M., Scheibel, T., Vorberg, I. Prion protein/protein interactions: fusion with yeast Sup35p‐NM modulates cytosolic PrP aggregation in mammalian cells. FASEB J . 22, 762–773 (2008)