Nav: Home

New theory unlocks the secret behind protein-membrane interactions

January 24, 2019

Trillions of cells -- all different shapes and sizes -- form a human body's structure. Surrounding each cell is a membrane, jointly acting as hostess and security -- welcoming certain information into the cell while making sure its components don't spill out into the body's void. Much is known about how the individual pieces of a cell work, but a significant understanding of how proteins interact with the cell membrane has remained a mystery until now, following a recent study at the University of Missouri.

"When you think about the fundamental components of living systems, proteins are among the most important, right up there with nucleic acids," said Gavin King, an associate professor of physics in the College of Arts and Science at MU, and joint associate professor of biochemistry. "Proteins execute more activity in the cell compared to DNA."

Proteins are the workhorses of a cell. About 30 percent of proteins in any given cell frequently interact with membranes or reside within membranes in order to facilitate and regulate the flow of information and materials in and out of cells. Using high precision atomic force microscopy experiments, King's team measured the force required for proteins to break free from the membrane.

"Imagine you are going fishing, and your fishing rod is a force microscope," King said. "At the end of our fishing rod we attached a lure, or in this case a really short protein. In a very careful and controlled manner, we lower the fishing rod to the vicinity of a membrane. In a way we can't control or directly observe, the lure is frequently bitten by the fish, which in this case is the membrane. When the fish bites, we can pull the lure back and we can ask how much force it takes to pop the lure out of the fish's mouth. What surprised us is that if you do that same experiment repeatedly, you get different results. We were struggling to find a model that could fit this complexity."

To answer this question, Ioan Kosztin, a professor of physics in the College of Arts and Science at MU, partnered with King and developed a theoretical model that shows there is more than one way a protein can break free of the membrane involving several different pathways. They discovered that the protein-membrane interaction can exhibit a "catch-bond" behavior.

"Catch-bond behavior is similar to a Chinese finger trap, where counterintuitively, the harder one pulls on the trap, the stronger the trap pulls back," Kosztin said. "Though similar behavior has been previously described on a cellular level, to our knowledge, this is the first report for protein-membrane interactions."

The researchers hope this discovery will provide a foundation for future studies on signaling pathways in cells and how drugs vary cellular functions.
-end-
The study, "Multiple stochastic pathways in forced peptide-lipid membrane detachment" was published in Scientific Reports. Other contributors to the study include Milica Utjesanovic and Tina R. Matin who were graduate students at MU during the study, and Krishna P. Sigdel, a postdoctoral associate at MU during the study. Utjesanovic is currently a doctoral student in the MU department of physics and astronomy. Matin is a postdoctoral associate in anesthesiology at Weill Cornell Medicine in New York. Sigdel is an assistant professor of physics and astronomy at California State Polytechnic University, Pomona. This study was supported by the Burroughs Wellcome Fund Career Award at the Scientific Interface, a National Science Foundation Career Award (#1054832), and the MU Research Board. The computations were performed on MU's RCSS HPC infrastructure (NSF grant #CNS-1429294). The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agencies.

University of Missouri-Columbia

Related Proteins Articles:

Coupled proteins
Researchers from Heidelberg University and Sendai University in Japan used new biotechnological methods to study how human cells react to and further process external signals.
Understanding the power of honey through its proteins
Honey is a culinary staple that can be found in kitchens around the world.
How proteins become embedded in a cell membrane
Many proteins with important biological functions are embedded in a biomembrane in the cells of humans and other living organisms.
Finding the proteins that unpack DNA
A new method allows researchers to systematically identify specialized proteins called 'nuclesome displacing factors' that unpack DNA inside the nucleus of a cell, making the usually dense DNA more accessible for gene expression and other functions.
A brewer's tale of proteins and beer
The transformation of barley grains into beer is an old story, typically starring water, yeast and hops.
More Proteins News and Proteins Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...