Speaker
Description
Our understanding of cell division control still relies largely on interpreting correlations between phenomenological variables, with limited connection to the underlying molecular mechanisms.
In this talk, I present an analytically tractable stochastic threshold–accumulation model in which a size-dependent divisor protein triggers division upon reaching a noisy, autocorrelated threshold. This framework disentangles, within a unified theory, the roles of intrinsic and extrinsic noise, as well as key mechanistic features such as threshold reset and threshold memory. We show that these ingredients generate a much richer spectrum of behaviors than the commonly assumed adder, spanning continuously from timer to sizer-like strategies while modulating size fluctuations.
Comparison with single-cell E. coli data indicates that extrinsic noise and additional mechanistic ingredients are required to reproduce the observed variability. However, mechanisms that control fluctuations typically reshape the underlying division strategy. Strikingly, we identify a regime in which size fluctuations can be tuned independently of division control, preserving adder-like behavior even in the presence of extrinsic noise. This regime emerges from a balance between threshold correlations and threshold reset, extending the prevailing view that full reset is required for adder control. Altogether, this provides a direct mechanistic link between molecular noise and the emergent division laws observed in data.
