Destabilizing Interactions Among [PSI +] and [PIN +] Yeast Prion Variants

摘要

The yeast Sup35 and Rnq1 proteins can exist in either the noninfectious soluble forms, [ psi –]or[ pin –], respectively, or the multiple infectious amyloid-like forms called [ PSI +]or[ PIN +] prion variants (or prion strains). It was previously shown that [ PSI +] and [ PIN +] prions enhance one another's de novo appearance. Here we show that specific prion variants of [ PSI +] and [ PIN +] disrupt each other's stable inheritance. Acquiring [ PSI +] often impedes the inheritance of particular [ PIN +] variants. Conversely, the presence of some [ PIN +] variants impairs the inheritance of weak [ PSI +] but not strong [ PSI +] variants. These same [ PIN +] variants generate a single-dot fluorescence pattern when a fusion of Rnq1 and green fluorescent protein is expressed. Another [ PIN +] variant, which forms a distinctly different multiple-dot fluorescence pattern, does not impair [ PSI +] inheritance. Thus, destabilization of prions by heterologous prions depends upon the variants involved. These findings may have implications for understanding interactions among other amyloid-forming proteins, including those associated with certain human diseases.