Chapter 22 - Reconstitution of membrane symmetry breaking

Abstract

Our understanding of nature is often punctuated by consideration of symmetry. Natural processes are continuously transitioning between evolving structures that serve unique functions. One of the overarching themes in biology is the quest to unravel the molecular interactions that dictate the trajectories between these symmetry states. As biological systems operate via entangled, redundant, and nonlocal molecular interactions, the stepwise determination of these transition states is impossible. Therefore, a macroscopic view of symmetry in a biologically reduced context enables studies that are better tractable. Symmetry breaking events taking place at the membrane boundary dynamically translate the molecular interactions into membrane perturbations, such as in vesicular trafficking, cell division, and cell migration. Despite the significance, reduced membrane-bound systems encapsulating purified biomolecules within are generally challenging to assemble. Here, we present an overview of how closed membranes that mimic the biological context could be used to engineer systems that can depart from symmetries toward asymmetric architectures. This sharpens the reader’s understanding of the governing principles of symmetry breaking and inspires insights into how dynamic reorganization events drive key functions of a living cell.