Clearance of an amyloid-like translational repressor is governed by 14-3-3 proteins

Amyloids are fibrous protein aggregates associated with age-related diseases. While these aggregates are typically described as irreversible and pathogenic, some cells use reversible amyloid-like structures that serve important functions. The RNA-binding protein Rim4 forms amyloid-like assemblies that are essential for translational control during Saccharomyces cerevisiae meiosis. Rim4 amyloid-like assemblies are disassembled in a phosphorylation-dependent manner at meiosis II onset. By investigating Rim4 clearance, we elucidate co-factors that mediate clearance of amyloid-like assemblies in a physiological setting. We demonstrate that yeast 14-3-3 proteins bind to Rim4 assemblies and facilitate their subsequent phosphorylation and timely clearance. Furthermore, distinct 14-3-3 proteins play non-redundant roles in facilitating phosphorylation and clearance of amyloid-like Rim4. Additionally, we find that 14-3-3 proteins contribute to global protein aggregate homeostasis. Based on the role of 14-3-3 proteins in aggregate homeostasis and their interactions with disease-associated assemblies, we propose that these proteins may protect against pathological protein aggregates.