A new kind of cellular bond has been discovered by researchers at Iowa State University. Called catch bonds, they may be instrumental in keeping hearts functioning. When they break down, they may facilitate the spread of cancer to the rest of the body.

Sanjeevi Sivasankar describes catch bonds “nanoscale seatbelts” and says “When you pull on these proteins, they become stronger. Sivasankar is an ISU assistant professor of physics and astronomy and an associate of the U.S. Department of Energy’s Ames Laboratory. According to Sivasankar, this behavior is the opposite of the expected natural reaction: that force will weaken a bond.

Sivasankar is the author of a paper published online by Nature Communications, entitled “Resolving the molecular mechanism of cadherin catch bond formation”. Co-author Kristine Manibog, a graduate student in physics and astronomy and student associate of the Ames Laboratory, is moving ahead with their research. “The next step will be to find the…mechanism of ideal bonds,” said Manibog. With these bonds, “when you try to pull the proteins apart, [it] doesn’t matter how strong or how weak the force is,” said Manibog. In other words, these bonds would hold on regardless of stress or pressure.

The paper was also co-authored by Sabyasachi Rakshit, of the Indian Institute of Science Education and Research in Mohali, India, and Hui Li, of the Suzhou Institute of Biomedical Engineering and Technology of the Chinese Academy of Sciences in Suzhou New District, China. Both are former postdoctoral researchers at ISU under Sivansankar.

Catch bonds are formed by adhesion proteins called cadherins, named for the term “calcium-dependent adhesion”. These proteins are already known to play an important role in cellular adhesion. Two rod-shaped cadherins can bind together in the shape of an X, a formation called an X-dimer. When pulled, and in the presence of calcium ions, they form catch bonds. When the ions, or the force, was removed in experiments, the catch bond formation also vanished, leaving the cells free to spread.

Sivasankar is quick to point out that their findings are a step toward further discoveries and that any practical application requires more research. In terms of the role of catch bonds in spreading cancer, and the potential of their research in battling the disease, Sivasankar said “”I want to clarify that it’s just a hypothesis. It still remains to be shown.”

However, there may be other applications for the discovery. Engineers have occasionally turned to the advanced mechanisms of the human body to solve problems. “I could imagine many scenarios where this would be important in an engineering problem,” Sivasankar said. He described such bonds as hooks that resist force.

Although Sivasankar could not say when or how this discovery might be applied to solutions for disease, he hopes to research the findings further, and reinforces the role of catch bonds in the body. “You can think of these cadherins as sort of the body’s glue,” he said.

The team’s research was accomplished with the support of grants from the American Heart Association and the American Cancer Society.