Spatiotemporal control of condensates via oligomerization-dependent phase separation

Biomolecular condensates which form via liquid-liquid phase separation can be involved in cellular functions such as genome organization and expression. They are often spatially regulated by tuning multivalent interactions. By changing the oligomerization state, modern optogenetic tools, such as Corelets, can enable direct spatiotemporal control of condensates. Here, we establish a thermodynamic framework for the oligomerization-dependent phase separation and a dynamic model based on Cahn-Hilliard theory to study the partitioning of condensates due to local light activation. In agreement with optogenetic experiments, simulations show that it is possible to locally induce droplet formation, move droplets, exert forces, and even actuate the reorganization of viscoelastic chromatin loci via capillary forces. The simulations may aid the design of programmable and customizable spatiotemporal control of biomolecular condensates.