Role of protein-mRNA droplet formation in regulation of meiotic exit in yeast

Liquid-liquid phase separated condensates consisting of key molecules together with other proteins or RNA ensure the execution of a variety of cellular regulatory processes in a spatially and temporally controlled manner. The dynamic assembly, disassembly and clearance of amyloid-like aggregates of the translational repressor Rim4 in yeast has been shown to be essential for progression through meiotic divisions [Wang et al., Dev. Cell (2020)]. These aggregates sequester and prevent translation of mRNAs critical for exit from meiosis II. Multisite phosphorylation of Rim4 triggers disassembly of aggregates followed by autophagy of monomeric or oligomeric units, releasing mRNAs and enabling translation. We have developed a model informed by experiments for the meiosis II exit regulatory module. We present analytical and numerical results for the stochastic dynamics of the model that explore the role of Rim4-mRNA droplet formation in regulating noise and fidelity of exit.