Stochastic Reaction Networks Within Interacting Compartments with Content-Dependent Fragmentation
David F. Anderson, Aidan S. Howells, Diego Rojas La Luz
TL;DR
This work extends stochastic CRN modeling to dynamic compartments where fragmentation depends on intracellular content. Using Lyapunov-function methods, it derives general, verifiable conditions for non-explosivity and positive recurrence of the coarse-grained compartment model, under the assumption of a linear Lyapunov function for the underlying CRN and finite inflow moments. Crucially, it shows that the explosivity criteria from prior content-agnostic fragmentation results do not always carry over when fragmentation is content-dependent, providing mild sufficient conditions for non-explosivity and a positive recurrence framework applicable to phenomena such as cell division and intracellular transport. The results offer a rigorous theoretical foundation for content-mediated compartment dynamics and illuminate how feedback through fragmentation can shape long-term stochastic behavior of cellular-like systems.
Abstract
Stochastic reaction networks with mass-action kinetics provide a useful framework for understanding processes -- biochemical and otherwise -- in homogeneous environments. However, cellular reactions are often compartmentalized, either at the cell level or within cells, and hence non-homogeneous. A general framework for compartmentalized chemistry with dynamic compartments was proposed in (Duso and Zechner, PNAS, 2020), and the special case where the compartment dynamics do not depend on their contents was studied mathematically in (Anderson and Howells, Bull. Math. Biol., 2023). In the present paper, we investigate the case in which the rate of fragmentation of a compartment depends on the abundance of some designated species inside that compartment. The main focus of this work is on providing general conditions for (positive) recurrence and non-explosivity of the models. In particular, we demonstrate that the explosivity characterization from (Anderson and Howells, Bull. Math. Biol., 2023) fails in this setting and provide new sufficient conditions for non-explosivity and positive recurrence, under the assumption that the underlying CRN admits a linear Lyapunov function. These results extend the theoretical foundation for modeling content-mediated compartment dynamics, with implications for systems such as cell division and intracellular transport.