Navigation Links
Cell membranes behave like cornstarch and water
Date:11/3/2010

Mix two parts cornstarch and one part water. Swirl your fingers in it slowly and the mixture is a smoothly flowing liquid. Punch it quickly with your fist and you meet a rubbery solid -- so solid you can jump up and down on a vat of it.

It turns out that cell membranes or, more precisely the two-molecule-thick lipid sheets that form the structural basis of all cellular membranes -- behave the same way, say University of Oregon scientists.

For decades, researchers have been aware that biological membranes are fluid, and that this fluidity is crucial to allowing the motions and interactions of proteins and other cell surface molecules. The new studies, however, reveal that this state is not the simple Newtonian fluidity of familiar liquids like water, but rather it is viscoelastic. At rest the mixture is very fluid, but when quickly perturbed, it bounces back like rubber.

The discovery -- detailed Oct. 25 in the Early Edition of the Proceedings of the National Academy of Sciences -- strikes down the notion that these biologically important membranes are Newtonian fluids that flow regardless of the stress they encounter.

"This changes our whole understanding of what lipid membranes are," said Raghuveer Parthasarathy, a professor of physics and member of the UO's Materials Science Institute and Institute of Molecular Biology. "We may need to rethink our understanding of how all sorts of the mechanical processes that occur in cell membranes work, like how proteins are pulled from one place to another, how cells respond to stretching and other forces, and how membrane-embedded proteins that serve as channels for chemical signals are able to open and close.

"A lot of these mechanical tasks go awry in various diseases for reasons that remain mysterious," he said. "Perhaps a deeper understanding of the mechanical environment that membranes provide will illuminate why biology functions, or fails to function, in the way it does."

In the project, freestanding membranes of lipids -- fatty molecules that form the basis of all cell membranes -- were built with lipid-anchored nanoparticles as tracers that could be observed under high-powered microscopes. Close analysis of the trajectories of these particles allowed researchers to deduce the fluid and elastic properties of the membranes under changing conditions.

Leading the experiments were Christopher W. Harland, who earned a doctorate in physics from the UO last summer and is now a postdoctoral researcher at the University of Chicago, and Miranda J. Bradley, then a visiting undergraduate student from Portland Community College and now at Portland State University. Bradley studied in Parthasarathy's lab as part of the UO's Undergraduate Catalytic Outreach & Research Experiences (UCORE) program.

The importance of membrane fluidity has been recognized for decades, but membranes' strange character as a viscoelastic material has gone unnoticed, said Parthasarathy, who is among UO scientists involved in the Oregon Nanoscience and Microtechnologies Institute (ONAMI). "In retrospect, we shouldn't be surprised. Nature uses viscoelasticity in lots of its other liquids, from mucus to tears. Now we've found that it harnesses viscoelasticity in lipid membranes as well."


'/>"/>

Contact: Jim Barlow
jebarlow@uoregon.edu
541-346-3481
University of Oregon
Source:Eurekalert

Related biology news :

1. New microscopy technique reveals mechanics of blood cell membranes
2. Sticky protein helps reinforce fragile muscle membranes
3. How mitochondria get their membranes bent
4. Phytoplankton cell membranes challenge fundamentals of biochemistry
5. UC research: Rabbits food brings luck in decreasing estrogen levels in wastewater
6. Researchers developing real-time electronic monitoring for coastal waters
7. BOEMRE leads study of deepwater communities post-Deepwater Horizon spill
8. LSUHSC study IDs proteins regulating water retention in salt-sensitive hypertension
9. Everglades show improvement in water quality
10. Shaping the future of the High Plains water supply
11. Florida State study finds watermelon lowers blood pressure
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/9/2016)... Aware, Inc. (NASDAQ: AWRE ), a leading supplier ... fourth quarter and year ended December 31, 2015.  ... of 2015 was $6.9 million, an increase of 61% compared to ... the fourth quarter of 2015 was $2.6 million compared to $0.2 ... --> --> Higher revenue and operating income in ...
(Date:2/8/2016)... Czech Republic , February 8, 2016 /PRNewswire/ ... EU-regulated global payment platform which presents innovation for ... Biometrics Authentication feature called VoiceKey. --> ... platform which presents innovation for clients, comfort and ... called VoiceKey. --> Worldcore ...
(Date:2/4/2016)... 4, 2016 The field of Human ... the most popular hubs of the biotechnology industry. ... huge studies of human microbiota, have garnered a ... the microbiome space has literally exploded in terms ... This report focuses on biomedical aspects of research, ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... ... 2016 , ... Global Stem Cells Group, a ... Stem Cells Network (GSCN) to distribute exosome injection and other biological products to ... Rica, Dominican Republic, Colombia, Argentina, Nicaragua, Panama, El Salvador, Venezuela, Peru, Ecuador, Paraguay, ...
(Date:2/10/2016)... NX Prenatal Inc., a US based ... for early warning of adverse pregnancy outcomes, announced ... by Dr. Thomas McElrath of Brigham ... Medicine,s (SMFM) annual meeting held in ... The presentation reported initial positive top-line results regarding ...
(Date:2/10/2016)... , Feb. 10, 2016  Matchbook, Inc., ... for fast growing biotech companies, announced today the ... Procurement Strategic Advisor. Jim brings nearly 25 years ... and procurement, having spent nearly two decades in ... Chain/Logistics and Procurement at Genzyme and, most recently ...
(Date:2/10/2016)... ... 10, 2016 , ... PatientCrossroads announces that the ... online PatientCrossroads platform, has exceeded both its one-year and overall recruitment goals since ... which seeks to advance understanding of the hereditary risks for certain kinds of ...
Breaking Biology Technology: