Spatial and temporal control of lipid-membrane morphology induced by sphingomyelinase

[摘要] (cont.) At a physiologically relevant concentration of SMase, we observe that membrane composition can influence the formation of SM-enriched domains and the nucleation of SMase-features at different extents of time scale and thus significantly tune the stable duration of the middle pause morphology. More importantly, the induction time of SMase-feature nucleation can be significantly decreased by increasing the supersaturating level of its three components in the membrane system. We further model the spatio-temporal morphology change during the solvent-mediated phase transformation. Three major kinetic processes are described in the model: the consumption of SM by the enzymatic reaction at an SMase-feature, the diffusion of SM from SM-enriched domains to an SMase-feature, and the release of SM due to the dissolution of SM-enriched domains. We combine MATLAB coding with Comsol, a software using finite element method to solve partial differential equations, to solve the model numerically due to the complex geometry and the moving boundary of our membrane systems. The non-dimensionality of the model allows the system to be characterized by three non-dimensional parameters. We show all of the possible scenarios of spatial pattern change during the phase transformation. The modeling results are shown to be consistent with our experimental results and can provide insights into the system parameters which are difficult to measure.

[发布机构] Massachusetts Institute of Technology