Surfing Biological Surfaces: Transport and Positioning by Moving ATPase Gradients

Positional information has long been thought to be communicated mainly by cytoskeletal elements. My work has identified a novel mode of motility that is inherently different from microtubule- or actin-based transport, whereby protein gradients on a biological surface, such as a condensed chromosome or a lipid bilayer, can be used to position DNA or the cell division machinery, respectively. We developed a cell-free technique to visualize spatial organization on biological surfaces, and successfully reconstituted the gradient-forming systems required for bacterial DNA segregation and cell division positioning. This work provides the first direct demonstration of this non-filament-based mechanism in a biological context and establishes a new class of intracellular transport. We anticipate that surface-mediated protein gradients will emerge as a versatile way to control subcellular organization throughout all kingdoms of life.