A proteostasis clock underlies the timing of bacterial dormancy and antibiotic tolerance

Dormancy, characterized by an extended lag time before resuming growth, protects bacteria from antibiotic stress and facilitates the emergence of resistance. However, a common mechanism that precisely regulates bacterial lag time remains poorly defined. Here we show that the formation and disassembly dynamics of protein aggregates function as a proteostasis clock that governs the lag time distribution. By tracking the aggregate and regrowth dynamics of thousands of cells, we observed that dormant bacteria from diverse genetic and environmental contexts converge to delayed aggregate disassembly as a common rate-limiting step for growth resumption. Mechanistically, the chromosomal replication initiator DnaA is sequestered in aggregates and spatially separated from the nucleoid, thereby preventing DNA replication until proteostasis restoration enables aggregate disassembly. We modulated bacterial lag time distribution by genetically and chemically targeting the proteostasis-replication axis. Remarkably, lag extension scales linearly with the disruption level of proteostasis across diverse backgrounds, indicating a universal coupling between dormancy and proteostasis. This proteostasis collapse renders dormant bacteria, including clinical isolates, more sensitive to additional proteotoxic stress. These findings reveal a timekeeping mechanism in cellular dormancy, highlighting proteostasis as a shared target for combating antibiotic tolerance.