ATPase-Dependent Enzyme Activity Modulates the Dynamics of a Model Biological Condensate

Biological condensates are phase-separated ribonucleoprotein bodies that occur within cells. These concentrated phases are biochemical organizing centers of the cell, used to spatiotemporally control specialized biochemical reactions. Energy-dependent enzyme activity is thought to tune dynamics within condensates, with enzymes such as helicases, unfoldases, and chaperones implicated in this function. However, little direct evidence exists for energy and enzyme mediated condensate dynamics, and mechanisms for these processes remain unclear. One candidate family of proteins for regulating condensate dynamics is the DEAD-box helicase. These proteins are often found associated with cellular condensates, and mutations or deletions often affects the morphology, localization, and dynamics of their host condensates. However, how the activities of these enzymes affect the dynamics of biomolecular condensates has not been systematically explored. Here, we use the model phase-separating DEAD-box helicase LAF-1. Particle tracking shows how reconstituted LAF-1 condensates respond to different RNAs and nucleotides. By coupling these observations to biochemical data about LAF-1, we are building an understanding of how helicase activity can modulate condensate microenvironments.