Studies on dynamic control and cellular delivery of artificial phase-separated protein liquid condensates

Abstract

The liquid-like protein condensate generated by the intracellular biomolecular phase separation phenomenon is the basic principle for the formation of various kinds of membrane-less organelles inside the cell, and the formed organelles are the basis of biological metabolic pathways and the mechanisms by which organelles play their roles. The resulting protein condensates have the advantages of free internal and external mass exchange, the ability to recruit high concentrations of biomolecules into the condensate, and specific physical properties such as liquid, gel, and solid. These characteristics of protein condensates have attracted interest in applied research through the synthesis of cell-mimicking artificial organelles outside the cell. In this paper, I designed a strategy to generate a condensate model that can modulate the dynamics of protein phase separation condensates through additional material processing and reversibly transition between liquid, gel, and solid phases. The model was able to improve the stability and duration of the condensate to external changes by modifying the internal dynamics of the condensate, and confirmed its potential as a cell-mimicking artificial organelle by confirming its biological activity inside. Next, I designed a material delivery strategy to the inside of the cell using protein phase separation condensate. Phase separation condensates were generated from different types of proteins by metal ion induction and processed directly into cells. The formation of condensates and the efficiency of material delivery to cells varied depending on the type of protein, size, charge, and time of condensate formation. The developed phase separation condensate biomolecular delivery system is simple to produce and contains high efficiency biomolecules inside the condensate. These results provide a direction for evaluating their potential as biomolecular carriers and improving their delivery efficiency.