The yeast RNA binding protein PUB1 contains a prion-like domain (PrLD) and, when overexpressed, localizes into cytoplasmic liquid droplets and is toxic. However, truncated versions lacking the PrLD are either soluble or aggregating and do not significantly alter yeast growth. Analysis of the interactomes of WT and mutant PUB1 was analyzed to clarify the link between droplets formation and toxicity.