A protein required for the earliest steps in embryonic development also plays a key role in solidifying fear memories in the brains of adult animals, scientists have revealed. An apparent "hub" for changes in the connections between brain cells, beta-catenin could be a potential target for drugs to enhance or interfere with memory formation.
The results are published online this week and appear in the October issue of Nature Neuroscience.
The protein beta-catenin acts like a Velcro strap, fastening cells' internal skeletons to proteins on their external membranes that connect them with other cells. In species ranging from flies to frogs to mice, it also can transmit early signals that separate an embryo into front and back or top and bottom.
During long-term memory formation, structural changes take place in the synapses the connections between neurons in the brain, says Kerry Ressler, MD, PhD, associate professor of psychiatry and behavioral sciences at Emory University School of Medicine. Ressler is a researcher at Emory University's Yerkes National Primate Research Center, where the research was conducted, and a Howard Hughes Medical Institute investigator.
"We thought beta-catenin could be a hub for the changes that take place in the synapses during memory formation," says Ressler. "But because beta-catenin is so important during development, we couldn't take the standard approach of just knocking it out genetically."
He and graduate student Kimberly Maguschak used a variety of approaches to probe beta-catenin's role in fear memory formation, such as stabilizing the protein with a pulse of the psychiatric drug lithium and injecting a virus that could remove the gene for beta-catenin from brain cells.
If mice are electrically shocked just after they hear a certain tone, they gradually learn to fear that tone, and they show that fear by freezing.
To test beta-catenin's involvement i
|Contact: Kathi Baker|