Abstract
The self-organization of pattern-forming systems depends not only on the
chemical but also physical properties of their components. In this work, we
fragmented and dispersed the MinDE protein system's lipid substrate into
diffusive sub-micrometer-sized liposomes, and report that the ATP-fueled
protein-protein interactions continue to drive spatially extended patterns at
scales well separated from those of the requisite liposomes, despite the
complete loss of membrane continuity. The patterns form in three-dimensions
because the membrane is dispersed in a volume. By varying protein
concentration, liposome size distribution, and density, we observed and
characterized rich 3D dynamical patterns at steady state, including traveling
waves, dynamical spirals and a mixed phase where both patterns coexist.
Simulations and linear stability analysis of a coarse-grained model reveal that
the dispersed membranes's physical properties effectively rescale two key
factors that govern pattern formation and wavelength selection:
protein-membrane binding rates and diffusion. This work highlights the
robustness of pattern formation in membrane-bulk systems despite membrane
fragmentation. It suggests that biological protein systems have the potential
to serve as adaptable templates for out-of-equilibrium self-organization in 3D,
beyond in vivo biological contexts.