Molecular motor has a ‘gear’ for directional switching

CORVALLIS, Ore.—A study recently published in Nature Communications by researchers at Oregon State University (OSU), Henan University in China and the Uniformed Services University of the Health Sciences in Maryland points to a “gear” used by molecular motors for directional switching. This research, led by Weihong Qiu, an assistant professor of physics in the College of Science at OSU, is said to provide a new understanding of the complex cellular machinery that animal and fungi cells use to ensure normal cell division.

According to OSU, this new understanding revealed “a totally unexpected behavior” about a motor protein that functions as chromosomes are segregated during cell division and this new knowledge could, in particular, one day lead to new treatment approaches for certain types of cancers.

Motor proteins are tiny molecular “machines” that convert chemical energy into mechanical work. They are, in essence, miniature vehicles in a cell that move on a network of tracks commonly referred to as the cytoskeleton.

As OSU noted, “They shuttle cellular cargos between locations and generate forces to position chromosomes. But in spite of intensive research efforts over many years, mechanisms underlying the actions of many motor proteins are still unclear.”

This study focused on a particular motor protein called KlpA and used a high-sensitivity light microscopy method to directly follow the movement of individual KlpA molecules on the cytoskeleton track. They discovered that KlpA is able to move in opposite directions, which the researchers say was an unusual finding—KlpA-like motor proteins were thought to be exclusively one-way vehicles.

The researchers also discovered that KlpA contains a gear-like component that enables it to switch direction of movement. This allows it to localize to different regions inside the cell so it can help ensure that chromosomes are properly divided for normal cell division.

“In the past, KlpA-like motor proteins were thought to be largely redundant, and as a result they haven’t been studied very much,” Qiu said. “It’s becoming clear that KlpA-like motors in humans are crucial to cancer cell proliferation and survival. Our results help better understand other KlpA-like motor proteins including the ones from humans, which could eventually lead to novel approaches to cancer treatment.”

“KlpA is a fascinating motor protein because it is the first of its kind to demonstrate bidirectional movement,” Qiu added. “It provides a golden opportunity for us to learn from Mother Nature the rules that we can use to design motor protein-based transport devices. Hopefully in the near future, we could engineer motor protein-based robotics for drug delivery in a more precise and controllable manner.”