Navigation Links
New study defines the long-sought structure of a protein necessary for cell-cell interaction
Date:1/6/2013

JUPITER, FL, January 6, 2012 Scientists know that cells in all higher organisms cells need to bind to each other for the development, architecture, maintenance and function of tissues. Mysteries have remained, however, about exactly how cells manage this feat.

Scientists from the Florida campus of The Scripps Research Institute (TSRI) have now solved part of this puzzle by defining the structure of a protein known as α-catenin, which is essential to this process.

The work was published online ahead of print on January 6, 2012, by the journal Nature Structural & Molecular Biology.

Chain, Chain, Chain

Our cells bind to each other using specialized cell surface adhesion complexes called adherens junctions, which direct the formation of tight, Velcro-like contacts among cells.

Adherens junctions are made up of three types of proteinscadherin, α-catenin and β-catenin. First, cadherin receptors, which span the cell membrane, direct the binding of cells to each other using domains that project outside the cell. Second, their tail domains, found on the inside of the cell, bind to the protein β-catenin, which, in turn, is bound to α-catenin.

The term catenin is derived from the Latin word for chain, catena, and these three proteins literally make a chain. This complex is then stabilized when the end of the chain, α-catenin, attaches to the molecular framework of the cell, the cytoskeleton. Without this, link cells would simply be amorphous piles of goo. Furthermore, alterations of cadherins, β-catenin and/or α-catenin can lead to marked changes in cell signaling, growth and migrationwhich can result in abnormalities and cancer.

Confronting a Paradox

Exactly how α-catenin provides links to the cytoskeleton and to the cadherin-β-catenin complex, however, has long puzzled scientists.

Scientists have known that α-catenin forms links to the cytoskeleton by binding to a protein called F-actin (the "F" stands for filament), which is found in species ranging from yeast to humans. The paradox for scientists has been that, despite being able to bind to F-actin on its own, when bound to α-catenin α-catenin cannot bind to F-actin. That is, the binding of α-catenin to F-actin and to β-catenin are, in the test tube, mutually exclusive. So how does α-catenin bind to F-actin versus β-catenin and how is the final link in the chain stabilized in cells?

To resolve this paradox, the scientists crystallized and determined the structure of a nearly full-length human α-catenin. This structure showed why α-catenin cannot simultaneously bind to F-actin and β-catenin. Specifically, in its unbound state, α-catenin was shown to be an asymmetric dimer, where the two subunits have remarkable differences in their architecture that appear to together create the binding site for F-actin. Binding of β-catenin to α-catenin disrupts the interaction of its two subunits, changing its architecture and displacing F-actin.

The second part of the puzzlehow cadherin-β-catenin and α-catenin-F-actin complexes are linked together in cellswas resolved when the scientists realized that another cytoskeleton protein called vinculin, which can also bind to F-actin, plays a critical role in this process. The scientists established the structures of dimeric α-catenin alone and when in complex with pre-activated vinculin. The results showed that vinculin binding did not disrupt the α-catenin dimer and that both partners of the vinculin-α-catenin complex were in fact capable of binding to F-actin, a scenario that stabilizes adhesion complexes.


'/>"/>

Contact: Eric Sauter
esauter@scripps.edu
267-337-3859
Scripps Research Institute
Source:Eurekalert  

Related biology news :

1. Study by UC Santa Barbara researchers suggests that bacteria communicate by touch
2. Law that regulates shark fishery is too liberal: UBC study
3. New study will help protect vulnerable birds from impacts of climate change
4. Study jointly led by UCSB researcher supports theory of extraterrestrial impact
5. BYU study: Using a gun in bear encounters doesnt make you safer
6. 15-year study: When it comes to creating wetlands, Mother Nature is in charge
7. Pycnogenol (French maritime pine bark extract) shown to improve menopause symptoms in new study
8. Crystal structure of archael chromatin clarified in new study
9. EU-funded study underlines importance of Congo Basin for global climate and biodiversity
10. University of Houston study shows BP oil spill hurt marshes, but recovery possible
11. Study demonstrates cells can acquire new functions through transcriptional regulatory network
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
New study defines the long-sought structure of a protein necessary for cell-cell interaction
(Date:6/16/2016)... 16, 2016 The global ... to reach USD 1.83 billion by 2024, according ... Inc. Technological proliferation and increasing demand in commercial ... to drive the market growth.      ... The development of advanced multimodal techniques for biometric ...
(Date:6/7/2016)... , June 7, 2016  Syngrafii Inc. ... a business relationship that includes integrating Syngrafii,s patented ... branch project. This collaboration will result in greater ... the credit union, while maintaining existing document workflow ... http://photos.prnewswire.com/prnh/20160606/375871LOGO ...
(Date:6/2/2016)... Perimeter Surveillance & Detection Systems, ... Infrastructure, Support & Other Service  The latest ... comprehensive analysis of the global Border Security market ... of $17.98 billion in 2016. Now: In ... in software and hardware technologies for advanced video surveillance. ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... June 27, 2016  Global demand for enzymes ... through 2020 to $7.2 billion.  This market includes ... cleaning products, biofuel production, animal feed, and other ... and biocatalysts). Food and beverages will remain the ... increasing consumption of products containing enzymes in developing ...
(Date:6/27/2016)... CA (PRWEB) , ... June 27, 2016 , ... ... for clinical trials, announced today the Clinical Reach Virtual Patient Encounter CONSULT ... care circle with the physician and clinical trial team. , Using the CONSULT module, ...
(Date:6/27/2016)... 27, 2016   Ginkgo Bioworks , a leading ... was today awarded as one of the World ... world,s most innovative companies. Ginkgo Bioworks is engineering ... real world in the nutrition, health and consumer ... with customers including Fortune 500 companies to design ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... Researchers at ... most commonly-identified miRNAs in people with peritoneal or pleural mesothelioma. Their findings are the ... read it now. , Diagnostic biomarkers are signposts in the blood, lung fluid ...
Breaking Biology Technology: