Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers find the mechanism that forms cell-to-cell catch bonds

06.06.2014

Certain bonds connecting biological cells get stronger when they’re tugged.

Those bonds could help keep hearts together and pumping; breakdowns of those bonds could help cancer cells break away and spread.


This ribbon diagram shows a pulling force applied to two common adhesion proteins called cadherins (red and blue) bound together in an X-shape. The green spheres represent calcium ions while the cyan and orange stick figures correspond to amino acids brought together as the force is applied. The hydrogen bonds that form between the amino acids create catch bonds that get stronger when pulled. Larger image. Image courtesy of Sanjeevi Sivasankar

Those bonds are known as catch bonds and they’re formed by common adhesion proteins called cadherins. Sanjeevi Sivasankar, an Iowa State University assistant professor of physics and astronomy and an associate of the U.S. Department of Energy’s Ames Laboratory, has described catch bonds as “nanoscale seatbelts. They become stronger when pulled.”

But how does that happen? How can bonds get stronger under force? Sivasankar and his research team have found long-lived, force-induced hydrogen bonds are the answer. A paper describing their findings, “Resolving the molecular mechanism of cadherin catch bond formation,” has just been published online by Nature Communications. Sivasankar is the corresponding author.

Co-authors are Kristine Manibog, an Iowa State graduate student in physics and astronomy and a student associate of the Ames Laboratory; Hui Li, of the Suzhou Institute of Biomedical Engineering and Technology of the Chinese Academy of Sciences in Suzhou New District, China; and Sabyasachi Rakshit, of the Indian Institute of Science Education and Research in Mohali, India. Li and Rakshit are former postdoctoral researchers in Sivasankar’s laboratory.

The team’s research was supported by grants from the American Cancer Society and the American Heart Association. Sivasankar said strong cell-to-cell bonds are important to heart health and fighting cancer. He said the bonds connecting heart cells have to withstand constant mechanical forces. And, in some cancers, he said bonds no longer resist forces, allowing cancer cells to detach and spread.

To find the mechanism behind the strong ties created by catch bonds, Sivasankar’s research team began with molecular dynamics and steered molecular dynamics computer simulations based on data from previous experiments. They found that two rod-shaped cadherins bound together in an X-shape (called an X-dimer) form catch bonds when pulled and in the presence of calcium ions.

The calcium ions keep the cadherins rigid and ordered while the pulling brings parts of the proteins closer together. All of that allows a series of hydrogen bonds to form. These long-lived, force-induced hydrogen bonds lock the X-dimers into tighter contact. Sivasankar said the researchers followed up the simulations with single-molecule experiments using atomic force microscopy.

The experiments confirmed that cadherin X-dimers, when pulled and exposed to high calcium ion concentrations, formed catch bonds. Take away the force or the calcium ions, and catch bond formation was eliminated.

All of this, Sivasankar said, helps explain the biophysics of cell-to-cell adhesion. And that’s important to all of us. “Robust cadherin adhesion,” the researchers wrote in their paper, “is essential for maintaining the integrity of tissue such as the skin, blood vessels, cartilage and muscle that are exposed to continuous mechanical assault.”

Sanjeevi Sivasankar | Eurek Alert!
Further information:
http://www.news.iastate.edu/news/2014/06/05/catchbonds

More articles from Life Sciences:

nachricht Ambush in a petri dish
24.11.2017 | Friedrich-Schiller-Universität Jena

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>