Researchers report online in Nature Neuroscience that they've connected neuregulin-1 (Nrg-1), a protein linked to schizophrenia, and postsynaptic density protein-95 (PSD-95), a protein associated with Alzheimer's disease. The print version appears during the first week of November.

Nrg-1 originally caught scientists' attention because of its links to processes that encode memory in nerve cells. Scientists later found mutations in the Nrg-1 gene increased risk of schizophrenia in Scottish and Icelandic populations.

Nrg-1 is positioned in the outer membrane of nerve cells, with a portion hanging outside the nerve cell and another part jutting inside it. The exterior portion, known as Nrg-ECD, contributes to the formation of synapses, areas where two nerve cells communicate across a small physical gap, and to other aspects of nervous system development and communication.

Until recently, researchers gave little attention to Nrg-ICD, the interior portion of Nrg-1. But Jianxin Bao, Ph.D., research assistant professor of otolaryngology at Washington University and other scientists have begun amassing evidence that Nrg-ICD might be as important or even more important than Nrg-ECD.

"In a comparison of the frog and human genes, we earlier showed that Nrg-ICD was 87 percent identical between the two species," says Bao, who is first author of the new study. "When part of a protein is kept mostly unchanged for so long over the course of evolution, it suggests that part has some very important contributions to make."

Scientists knew that stimulation of a nerve cell causes Nrg-ECD to break off. In a previous experiment, Bao and colleagues a
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Contact: Michael C. Purdy
purdym@wustl.edu
314-286-0122
Washington University School of Medicine
28-Oct-2004