Interactions between Phase-Separated Liquids and Membrane Surfaces

Liquid-liquid phase separation has recently emerged as an important fundamental organizational phenomenon in biological settings. Most studies of biological phase separation have focused on droplets that condense from solution above a critical concentration, forming so-called membraneless organelles suspended in solution. However, membranes are ubiquitous throughout cells, and many biomolecular condensates interact with membrane surfaces. Such membrane-associated phase-separated systems range from clusters of integral or peripheral membrane proteins in the plane of the membrane to free, spherical droplets wetting membrane surfaces to droplets containing small lipid vesicles. In this review, we consider phase-separated liquids that interact with membrane surfaces and we discuss the consequences of those interactions. The physical properties of distinct liquid phases in contact with bilayers can reshape the membrane, and liquid-liquid phase separation can construct membrane-associated protein structures, modulate their function, and organize collections of lipid vesicles dynamically. We summarize the common phenomena that arise in these systems of liquid phases and membranes.

Automated summary

Liquid-liquid phase separation in biological settings, specifically those interacting with membrane surfaces, play a crucial role in reshaping membranes, constructing protein structures, modulating functions, and organizing lipid vesicles dynamically. This review discusses the fundamental organizational phenomenon of phase-separated liquids in contact with bilayers and summarizes the common phenomena arising from these interactions.