(Press-News.org) CAMBRIDGE, Mass. -- By creating a better way to see molecules at work in living brain cells, researchers affiliated with MIT's Picower Institute for Learning and Memory and the MIT Department of Chemistry are helping elucidate molecular mechanisms of synapse formation. These studies could also help further understanding of how synapses go awry in developmental diseases such as autism and Fragile X syndrome. The study will appear in the Oct. 7 issue of Cell.
Using the new technique, which is more accurate and sensitive than existing methods, the researchers found that certain protein-protein interactions can affect early phases of synapse maturation. Their work will help scientists understand exactly how two adjacent neurons form a synapse—the meeting point where information transfer among brain cells occurs. This method provides information on the dynamics of proteins in synapses on a minute-by-minute time scale, the researchers said.
"How nascent contacts mature into excitatory or inhibitory synapses is an area of intense interest," said Amar Thyagarajan, Autism Speaks Postdoctoral Fellow in the laboratory of Alice Y. Ting, associate professor of chemistry. "Trans-synaptic signaling complexes seem like a good place to start looking for clues to this process since they mediate signaling into the pre- and post-synaptic cells during this process."
Study co-authors Thyagarajan and Ting are Picower Institute affiliates.
The researchers studied the interaction of the proteins neurexin and neuroligin on the surface of neurons. These adhesion molecules--two of many in the brain that regulate synapse formation, maturation, function and plasticity--not only function as the "glue" that hold neurons together but also mediate signaling so that the appropriate molecular components are recruited for the pre- and postsynaptic cells.
Neurexins and neuroligins can be thought of as a chemical bridge and communication network that spans the synaptic cleft.
Called BLINC (Biotin Labeling of Intercellular Contacts), the new technique creates a fluorescent signal only when neurexin and neuroligin interact. "The only way for a BLINC signal to occur is when two neurons contact each other," Thyagarajan said.
For a long time, it had been known that neurexins and neuroligins are important for synapse maturation. However, their exact function was unclear since most previous studies used indirect methods such as manipulating gene expression to infer function.
"Our motivation was that if we could come up with a way to directly observe this complex, then maybe we could better understand its function in synapse maturation," Thyagarajan said.
"We developed BLINC to visualize this complex in live synapses in culture. We then used BLINC in different modalities to discover that synaptic activity causes the neurexin-neuroligin complex to grow in size," he said. "This growth is necessary for the recruitment of AMPA receptors to young synapses.
"AMPA receptor recruitment is a hallmark of excitatory synapse maturation, so our study demonstrated how a trans-synaptic complex can affect early phases of synapse maturation," Thyagarajan said.
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Source: "Imaging Activity-Dependent Regulation of Neurexin-Neuroligin Interactions Using trans-Synaptic Enzymatic Biotinylation," by Amar Thyagarajan and Alice Y. Ting. Cell, 7 October, 2010.
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WASHINGTON—October 7, 2010—The U.S. invested $139 billion last year in health research from all public and private sources, according to Research!America's latest annual estimate. That amount represents only 5.6% of the $2.47 trillion overall U.S. health spending in 2009—or 5.6¢ of every health dollar—which varies no more than 0.2% from 2005 levels.
The estimate is available here: http://www.researchamerica.org/uploads/healthdollar09.pdf.
The 2009 investment grew by only 0.1% over 2008. This small increase can be attributed largely to the federal stimulus funding ...
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Scheeline developed a method using a few basic, inexpensive supplies and a digital camera to build a spectrometer, an important basic chemistry instrument. Spectrophotometry is one of the most widely used means for identifying and quantifying materials in both physical and biological sciences.
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An approach pioneered by researchers at North Carolina State University gives scientists new insight into the way silicon bonds with other materials at the atomic level. This technique could lead to improved understanding of and control over bond formation at the atomic level, and opportunities for the creation of new devices and more efficient microchips.
Manufacturers build silicon-based devices from layers of different materials. Bonds – the chemical interaction between adjacent atoms – are what give materials their distinctive characteristics. "Essentially, a bond ...
New Haven, Conn.—A team of Yale University scientists has engineered the cell wall of the Staphylococcus aureus bacteria, tricking it into incorporating foreign small molecules and embedding them within the cell wall.
The finding, described online in the journal ACS Chemical Biology this week, represents the first time scientists have engineered the cell wall of a pathogenic "Gram-positive" bacteria—organisms responsible not only for Staph infections but also pneumonia, strep throat and many others. The discovery could pave the way for new methods of combating the bacteria ...
WEST LAFAYETTE, Ind. - A study by researchers at Purdue University suggests that some high school football players suffer undiagnosed changes in brain function and continue playing even though they are impaired.
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The findings represent a dilemma because they suggest athletes may suffer a form ...
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Susan M. Reverby, a professor at Wellesley College, describes how she unearthed documents about the study by accident while doing research for a book on the Tuskegee syphilis study. The documents, hidden in the ...
Talk about a walk on the wild side: University of Notre Dame researcher Joshua Shrout is co-author of a new paper that shows that bacteria are capable of "standing up" and moving while vertical.
Shrout, assistant professor of civil engineering and geological sciences and a member of the Eck Institute for Global Health, has been studying the surface motility of bacteria since 2004. In 2008, UCLA researcher Gerard Wong suggested that an undergraduate bioengineering senior design group that he was advising track the bacterium Shrout was studying. After some interesting patterns ...
