Figure 1.

Liquid‐liquid phase separation of RNPs and decreased reversibility. At a critical concentration, monomeric RNPs are partitioned into reversible liquid droplets in a heterotypical manner, illustrated by different colors of low‐complexity RBPs. The presence of RNA (drawn as “snakes”) together with dynamic, multiple weak interactions between intrinsically disordered protein regions (not shown), seems critical for droplet formation. In hydrogels, the interactions between the disordered regions are less dynamic because of cross‐β conformations, and hydrogels appear to exhibit a broad spectrum of reversibility. Formation of amyloid‐like inclusions of low reversibility, associated with disease mutations, is shown at the right. Partitioning of RNPs into droplets/hydrogels increases their local concentration by orders of magnitude 38 and thereby the likelihood of fibrillization.