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Accepted · first revision · record

Title: Mechanism of liquid-to-solid aging of condensates
Plain: Some protein droplets slowly harden from liquid to gel or solid over hours, and in disease they can turn into fibers. What molecular process drives this hardening and sets its rate is unknown.
Precise: For FUS and hnRNPA1 condensates in vitro, viscosity and elastic modulus increase over hours (aging of a Maxwell fluid). Determine whether aging is driven by $\beta$-sheet formation and fibril nucleation inside the dense phase, by glass-like slowing of sticker exchange, or by both, and predict the aging time as a function of sequence and temperature.
Settled by: Time-resolved rheology combined with structural probes of beta-sheet content on sequence variants, matched by a model that predicts aging times.
Kind: well-posed
Answer type: mechanism
References: (empty)
Literature status: open
Status note: (empty)
Posed since: (empty)