Probing and Reprogramming Phase-Separated Liquid Compartments in Living Cells

Cells coordinate complex cellular tasks by confining biomolecules of shared function using various compartmentalization strategies. Membraneless compartments are dynamic RNA and protein-rich subcellular assemblies with liquid-like properties of important physiological significance that provide a better fit for some cellular tasks as compared to membranous compartments. While the transient and dynamic nature of membraneless compartments has hampered their research for many decades, the recent realization that they represent phase-separated condensates has provided a valuable biophysical framework for understanding their physiology and rationally designing new experimental approaches. In this talk, I will present controllable bioengineered tools that allow probing and manipulating the intracellular phase behavior and the reprogramming of the spatial organization and material properties of reconstituted synthetic condensates as well as native liquid bodies. We have used these technologies to map protein-specific phase diagrams in live cells. These quantitative representations of the tendency of a protein to phase-separate provide access to the underlying energy landscape of the cell, yielding cell-state-dependent and sequence-specific protein fingerprints. Intracellular phase-space mapping has also begun to provide quantitative insights into the poorly understood link between the propensity of disease-implicated proteins to phase-separate and the onset of pathological aggregation.