AMES, Iowa The human body has more than a trillion cells, most of them connected, cell to neighboring cells.
How, exactly, do those bonds work? What happens when a pulling force is applied to those bonds? How long before they break? Does a better understanding of all those bonds and their responses to force have implications for fighting disease?
Sanjeevi Sivasankar, an Iowa State assistant professor of physics and astronomy and an associate of the U.S. Department of Energy's Ames Laboratory, is leading a research team that's answering those questions as it studies the biomechanics and biophysics of the proteins that bond cells together.
The researchers discovered three types of bonds when they subjected common adhesion proteins (called cadherins) to a pulling force: ideal, catch and slip bonds. The three bonds react differently to that force: ideal bonds aren't affected, catch bonds last longer and slip bonds don't last as long.
The findings have just been published by the online Early Edition of the Proceedings of the National Academy of Sciences.
Sivasankar said ideal bonds the ones that aren't affected by the pulling force had not been seen in any previous experiments. The researchers discovered them as they observed catch bonds transitioning to slip bonds.
"Ideal bonds are like a nanoscale shock absorber," Sivasankar said. "They dampen all the force."
And the others?
"Catch bonds are like a nanoscale seatbelt," he said. "They become stronger when pulled. Slip bonds are more conventional; they weaken and break when tugged."
In addition to Sivasankar, the researchers publishing the discovery are Sabyasachi Rakshit, an Iowa State post-doctoral research associate in physics and astronomy and an Ames Laboratory associate; Kristine Manibog and Omer Shafraz, Iowa State doctoral students in physics and astronomy and Ames Laboratory student associates; and Yu
|Contact: Sanjeevi Sivasankar|
Iowa State University