Persistent activation of mRNA translation by transient Hsp90 inhibition
The heat shock protein 90 (Hsp90) chaperone functions as a protein-folding buffer and plays a unique role promoting the evolution of new heritable traits. To better understand how Hsp90 can affect mRNA translation we screened more than 1600 factors involved in mRNA regulation for physical interactions with Hsp90 in human cells. The mRNA binding protein CPEB2 strongly binds Hsp90 via its prion domain. In a yeast model, transient inhibition of Hsp90 resulted in persistent activation of a CPEB translation reporter even in the absence of exogenous CPEB that persisted for 30 generations after the inhibitor was removed. Ribosomal profiling revealed that some endogenous yeast mRNAs, including HAC1, show a persistent change in translation efficiency following transient Hsp90 inhibition. Thus, transient loss of Hsp90 function can promote a non-genetic inheritance of a translational state affecting specific mRNAs, introducing a new mechanism by which Hsp90 can promote phenotypic variation. Overall design: Ribosome-profiling data examining heat shock and Hsp90 inhibition in yeast.