Navigation Links
Cell membranes behave like cornstarch and water

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
University of Oregon

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:
(Date:11/17/2015)... PARIS , November 17, 2015 ... 17 au 19 novembre  2015.  --> Paris ... 2015.  --> DERMALOG, le leader de l,innovation ... à la fois passeports et empreintes sur la même ... pour les passeports et l,autre pour les empreintes digitales. ...
(Date:11/12/2015)... 2015  A golden retriever that stayed healthy despite ... has provided a new lead for treating this muscle-wasting ... Institute of MIT and Harvard and the University of ... Cell, pinpoints a protective gene that ... effects. The Boston Children,s lab of Lou Kunkel ...
(Date:11/10/2015)... LONDON , Nov. 10, 2015 /PRNewswire/ ... segmented on the basis of product, type, ... segments included in this report are consumables, ... this report are safety biomarkers, efficacy biomarkers, ... in this report are diagnostics development, drug ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... , November 25, 2015 ... Report is a professional and in-depth study on ...      (Logo: ) , ... the industry including definitions, classifications, applications and industry ... for the international markets including development trends, competitive ...
(Date:11/24/2015)... -- Halozyme Therapeutics, Inc. (NASDAQ: HALO ) will be presenting ... on Wednesday, December 2 at 9:30 a.m. ET/6:30 a.m. ... will provide a corporate overview. th Annual Oppenheimer ... p.m. ET/10:00 a.m. PT . Jim Mazzola , vice ... overview. --> th Annual Oppenheimer Healthcare Conference in ...
(Date:11/24/2015)... , Nov. 24, 2015  Clintrax Global, Inc., a worldwide provider ... , today announced that the company has set a new ... 391% quarter on quarter growth posted for Q3 of 2014 to ... and Mexico , with the establishment of an ... 2015. --> United Kingdom and ...
(Date:11/24/2015)... 2015 --> ... released by Transparency Market Research, the global non-invasive prenatal ... of 17.5% during the period between 2014 and 2022. ... Industry Analysis, Size, Volume, Share, Growth, Trends and Forecast ... market to reach a valuation of US$2.38 bn by ...
Breaking Biology Technology: