A generalized theoretical framework to investigate multicomponent actin dynamics.

The length of actin filaments is regulated by the combined action of hundreds of actin-binding proteins. While the roles of individual proteins are well understood, how they combine to regulate actin dynamics in vivo remains unclear. Recent advances in microscopy have enabled precise, high-throughput measurements of filament lengths over time. However, the absence of a unified theoretical framework has hindered a mechanistic understanding of the multicomponent regulation of actin dynamics. To address this, we propose a general kinetic model that captures the combined effects of multiple regulatory proteins on actin dynamics. We provide closed-form expressions for both time-dependent and steady-state moments of the filament length distribution. Our framework not only differentiates between various regulatory mechanisms but also serves as a powerful tool for interpreting current data and driving future experiments.