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Free keywords:
PHASE-SEPARATION; FLUORESCENCE CORRELATION; TERNARY MIXTURES; GIANT
VESICLES; FOLDING DNA; RAFTS; CHOLESTEROL; MODEL; NANOSTRUCTURES;
ORGANIZATIONChemistry; Materials Science; DNA origami; lipid membranes; phase separation; self-assembly;
Abstract:
Self-assembly of biological molecules and structures is a fundamental property of life. Whereas most biological functions are based on self-assembled proteins and protein complexes, the self-assembly of lipids is important for the spatial organization of heterogeneous cellular reaction environments and to catalyze cooperative interactions on/with membranes. Lipid domains or "rafts", which are known to selectively recruit proteins, play an important functional role in sorting and trafficking of membrane components between subcellular organelles. However, how the recruitment and interactions of proteins in turn contributes to the formation and turnover of these structures has not been systematically addressed, due to the large variety in membrane-protein features and their spatiotemporal dynamics. The small size and transient nature of lipid domains adds to the complexity in visualizing them in living cells. Here, DNA origami is presented as a programmable tool to mimic protein clustering and assembly on membranes and illustrate how nanometer sized lipid domains coalesce into visible domains upon origami self-assembly in defined patterns. Hence, the local membrane composition can be efficiently regulated by the self-assembly of peripheral membrane binders. This reinforces the hypothesis that lipid rafts in cells occur as a result of membrane-protein interactions and, in particular, protein self-assembly.
