Alteration of brain protein regulate...( DALLAS Aug. 17 2005 Researchers at U...)

The research sheds new light on the action of reelin, a protein known to be important in the nervous system. During development, reelin sends cues to migrating neurons, telling them where they're supposed to go. In adult mice, reelin has recently been implicated in the formation of memories, and reduced production of reelin has been associated with schizophrenia in humans.

In a report published in the Aug.18 issue of the journal Neuron, Dr. Joachim Herz, professor of molecular genetics and a member of the Center for Basic Neuroscience at UT Southwestern and the paper's senior author, studied an area of the brain called the hippocampus, which is important for learning. He and his colleagues focused on the interaction of reelin and two other molecules, Apoer2 and the NMDA receptor.

In the nervous system the NMDA receptor is embedded in the membrane of synapses gaps between nerve cells where it is involved in receiving signals from other nerve cells. Apoer2 is another receptor which is associated with the NMDA receptor. When reelin encounters the cell, it attaches to Apoer2, which then boosts the activity of the NMDA receptor by promoting a chemical modification of the part of the NMDA receptor inside the cell. The result of this modification is that signals being received by the nerve cell are amplified and better reception means better learning.

This transition in the primary function of Apoer2, from guiding neurons in the embryonic brain to regulating synaptic signaling, occurs around the time of birth. A small string of amino acids, the building blocks of proteins, gets added near one end of Apoer2 and is essential for this new function. Adding the new amino acids is similar to cut
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Contact: Aline McKenzie
aline.mckenzie@utsouthwestern.edu
214-648-3404
UT Southwestern Medical Center
17-Aug-2005