Conversion-limited phase separation in biological cells

Phase separation is not only ubiquitous in diverse physical systems, but also plays an important organizational role inside biological cells. However, experimental studies of intracellular biomolecular condensates (drops with condensed concentrations of specific collections of proteins and nucleic acids) have challenged the standard kinetic theories of phase separation. Specifically, the coarsening rates observed are unexpectedly slow for many intracellular condensates. Recently, a conversion-limited scheme of phase separation has been proposed to account for the in vivo observation of the slow coarsening kinetics of P granules, one of the most well known biomolecular condensates, in the model organism C. elegans. [1]. In conversion-limited phase separation, the bottleneck of the coarsening rate is the slow conversion of a condensate constituent between the state in the dilute phase and the condensate state. In this talk, I will first motivate the conversion-limited scheme through a rugged energy landscape picture, and then elucidate its emergent physics [2].

References:

[1] Folkmann A W, Putnam A, Lee C F and Seydoux G 2021 Regulation of biomolecular condensates by interfacial protein clusters Science 373 1218–24

[2] Lee C F 2021 Scaling law and universal drop size distribution of coarsening in conversion-limited phase separation Phys. Rev. Res. 3 043081