Fig. 2

Activation of calmodulin in Ca²⁺ microdomains. A Schematic representation of simulations of calmodulin activation involving five compartments (Q1–Q5). End view shows the spatial orientation of the center, original and split types (indicated by red, green, and blue squares respectively) of microdomain-layout used to release Ca²⁺ into the system. Calcium is removed at the Q5 region to maintain the expected overall Ca²⁺ concentration of approximately 1–2 µM. The top and bottom of the environment represent hard boundaries that constrain Ca²⁺ diffusion. B Effective average concentration (mol/L) of Ca²⁺ in each of the compartments over the course of the simulations. C Average saturation of two states of calmodulin (CaM_2 and CaM_4) in each compartment over the course of the simulations