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Weihong Qiu standing in front of beige wall

Discovery of reversible motor protein could shed light on cancer growth

Weihong Qiu, Assistant Professor in Biochemistry and Biophysics

It's amazing enough that the "motor" proteins in our cells move along little train-track like structures called microtubules, carry cargos, and build and maintain the mitotic spindle, the football-shaped macromolecular structures that animal and fungi cells depend on to ensure accurate chromosome segregation during cell division.

But now, according to a recent discovery by physicist Weihong Qiu, at least one motor protein is capable of reversing direction!

KLpA diagram

Click on image to see motion: The motor protein KLpA moves in one direction and switches to the opposite direction between a pair of microtubules. Illustration credit: KuoFu Tsung, Oregon State University

Qiu's Single-Molecule Biophysics Laboratory recently published a study in Nature Communications reporting on this unexpected mechanical property of a particular motor protein called KlpA. Using a high-sensitivity microscopy method to directly visualize the motion of individual KlpA molecules on microtubules,the Qiu team showed that, while all other KlpA-like motor proteins are believed to move in only one direction on the microtubule track, KlpA has a “reverse” gear that allows it to go in different directions. This enables KlpA to behave differently in when it is operating at different locations within the mitotic spindle.

The discovery of a reverse gear in KlpA has the potential to shed light on similar KlpA-like proteins in mammals that are implicated in cancer proliferation. Furthermore, understanding the design principle behind the bidirectional motion of KlpA may also guide the engineering of motor protein-based molecular devices for more controlled and targeted drug delivery.

Based on an article in The Spectrometer by Heidi Schellman.

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