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 Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>