Nature’s Solution to the Problem of Biological Logistics

The ability of cells to survive and participate in a community, such as the human body, requires a logistical network that distributes nutrients, cellular contents, and information at biologically reasonable time-scales. How does a robust, adaptable system emerge from the sum of individual hard-wired molecular agents operating in a noisy environment? For example, motor proteins deliver cargo along intracellular filaments to appropriate sites in a network of molecular compartments whose connectivity is slowly becoming elucidated. However, surprisingly little is known about what these motor proteins do, specifically, (1) where they go in cells, (2) what they transport, and (3) how their activity is regulated. To address these basic questions, we modified motor proteins so they could be visualized in live cells and recovered with their physical binding partners. Individual motor proteins were also removed from cells to determine the overall effect on different cellular trafficking pathways. We found that different motor proteins are targeted to unique sub-cellular compartments and identified regulatory proteins resident in these compartments that could serve as molecular postal codes, or otherwise regulate the cycle of cargo binding and release. Overall, this provides an example of a biological solution to managing complex systems using a limited number of components.