Synthetic protein condensates for cellular and metabolic engineering

Protein condensates are distinct structures assembled in living cells that concentrate molecules via phase separation in a confined subcellular compartment. In the past decade, remarkable advances have been made to discover the fundamental roles of the condensates in spatiotemporal control of cellular metabolism and physiology and to reveal the molecular principles, components and driving forces that underlie their formation. Here we review the unique properties of the condensates, the promise and hurdles for harnessing them toward purposeful design and manipulation of biological functions in living cells. In particular, we highlight recent advances in mining and understanding the proteinaceous components for creating designer condensates, along with the engineering approaches to manipulate their material properties and biological functions. With these advances, a greater variety of complex organelle-like structures can be built for diverse applications, with unprecedented effects on synthetic biology.