Moving while you're stuck; a mechanical model of binding facilitated transport in biological systems

Binding is broadly understood in many biological processes as a mechanism to localize molecules. Binding is also used to dictate particle motion through some biopolymer filters including the nuclear pore complex, the extracellular matrix and mucus membranes. In these cases, flexible polymers transiently bind to transported molecules. Here we describe a mechanical model to probe how binding and thermal motion can enable transport. A particle experiences random forces during binding and unbinding events while being constrained by attached tethers. This model provides insight into the mechanisms and design rules involved in binding-mediated transport in both biological and synthetic polymeric systems.