This same complexity is one reason designing experiments to exclusively probe one aspect of a cell's function can be near impossible in vivo, and yield results difficult to interpret. Eduard Buchner commented in his 1907 Nobel Lecture that ‘We are seeing cells more and more clearly as chemical factories, where the various products are manufactured in separate workshops, the enzymes acting as the overseers.’ The ability to keeps things separate sounds simple, and yet, behind the scenes lies hundreds of interacting proteins and precise pathways that orchestrate and permit a multitude of mini-reactions to occur independently, repeatedly and simultaneously in the space of one cell. Cell biologists have been intrigued for decades by the organisational abilities of cells and their clever methods of compartmentalisation. One of the cell's most ingenious skills is also one of its most simple: compartmentalisation. Cells are some of the most incredibly adept devices we know and understanding them is the first step towards manipulating and harnessing cells as machines and applying them in novel ways. This statement couldn't be more evident than in the stunningly complex and vastly interlinked systems that make up each and every living cell. As the oft-quoted physicist Richard Feynman said ‘nature's imagination is so much greater than man's, she's never going to let us relax.’ Introduction Scientists have long looked to nature to provide solutions to some of our greatest problems, from therapeutics and medical materials, to the environment and energy production. Thus, well-characterised minimal components might be predictably combined into functional, compartmentalised protocellular materials that can be engineered for wide-ranging applications. We argue that minimal machineries need to be developed and optimised for employment in artificial protocell systems rather than the complex environs of a living organism. We review different in vitro membrane models and how biophysical investigations of minimal systems combined with appropriate theoretical modelling have been used to gain new insights into the intricate mechanisms of these membrane nanomachines, paying particular attention to proteins involved in membrane fusion, fission and cytoskeletal scaffolding processes. Towards the goal of bottom-up assembly of compartmentalised protocells in synthetic biology, we believe it will be important to harness and reconstitute the membrane shaping and sculpting characteristics of natural cells. These organelles are dynamic structures whose membrane barriers are continually shaped, remodelled and scaffolded by a rich variety of highly sophisticated protein complexes. Compartmentalisation of cellular processes is fundamental to regulation of metabolism in Eukaryotic organisms and is primarily provided by membrane-bound organelles.

Protein scaffold minimal