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Oligopeptide repeats in the yeast protein Sup35p stabilize intermolecular prion interactions
Author(s) -
Parham Steven N.,
Resende Catarina G.,
Tuite Mick F.
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.9.2111
Subject(s) - oligopeptide , biology , yeast , saccharomyces cerevisiae , fungal prion , in vivo , conserved sequence , biochemistry , microbiology and biotechnology , peptide sequence , peptide , genetics , gene
The nuclear‐encoded Sup35p protein is responsible for the prion‐like [ PSI + ] determinant of yeast, with Sup35p existing largely as a high molecular weight aggregate in [ PSI + ] strains. Here we show that the five oligopeptide repeats present at the N‐terminus of Sup35p are responsible for stabilizing aggregation of Sup35p in vivo . Sequential deletion of the oligopeptide repeats prevented the maintenance of [ PSI + ] by the truncated Sup35p, although deletants containing only two repeats could be incorporated into pre‐existing aggregates of wild‐type Sup35p. The mammalian prion protein PrP also contains similar oligopeptide repeats and we show here that a human PrP repeat (PHGGGWGQ) is able functionally to replace a Sup35p oligopeptide repeat to allow stable [ PSI + ] propagation in vivo . Our data suggest a model in which the oligopeptide repeats in Sup35p stabilize intermolecular interactions between Sup35p proteins that initiate establishment of the aggregated state. Modulating repeat number therefore alters the rate of yeast prion conversion in vivo . Furthermore, there appears to be evolutionary conservation of function of the N‐terminally located oligopeptide repeats in prion propagation.