Collaborative Research: Assembly of non-lipid components by heterogeneous membranes

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Non Technical AbstractNon-lipid components coupled to lipid membranes directly interact with one another but also feel effective interactions through the membrane. In particular, phase transitions in non-lipid components vary significantly from the bulk when a subset of components is membrane-coupled. Some past work has explored these differences for membranes that are themselves homogeneous. The objective of the current study is to explore systems in which both membranes and non-lipid components are capable of experiencing miscibility phase transitions. These systems represent novel biomaterials in which membrane-based signals are actuated to non-membrane processes, similar to common themes in signaling pathways. The research will use thermodynamic simulations and experiments in two well-defined model systems: one incorporating polyelectrolytes that form liquid phases in the bulk, and a second utilizing engineered DNA origami tiles that assemble into two dimensional lattices when coupled to membranes. Technical AbstractLipid membranes form boundaries between animal cells and their environments and define some subcellular compartments, such as the cell nucleus and mitochondria. These membranes are primarily made of lipids, soap-like molecules that spontaneously form into fluid, flexible sheets that act as boundaries to large or charged molecules. Cell membranes also contain embedded proteins, which are more complicated molecular machines that carry out an array of biological functions. Within cells, the material properties of the membrane helps to organize some embedded proteins, and contributes to the assembly of larger structures that are tethered to the membrane. Cells take advantage of this coupling to transduce signals across membranes, or to sense chemical or mechanical changes to membrane properties. This project draws inspiration from cells to develop minimal systems to explore the fundamental concepts that underlie these biological processes. Researchers will explore the two well-controlled systems of charged polymers and engineered DNA origami tiles tethered to membranes, and will identify how membranes influence the organization and assembly of non-lipid components and how the organization of non-lipid components impact membranes. The long-term goal is to inspire new materials that can sense and respond to a wide range of environmental stimuli. The researchers will communicate their findings through publications, conference presentations, public lectures, and by incorporating research into undergraduate curricula. The principle investigators will train undergraduate and graduate students for careers in STEM fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.