Good news for prions?

Mad cow and memory: Prion-like proteins proposed to regulate neuronal
plasticity
By Brendan A Maher

Since their discovery in 1982, prions have been mostly associated with
deadly and devastating neurodegenerative disorders-notably variant
Creutzfeld-Jakob disease and bovine spongiform encephalopathy. Nevertheless,
some maintain that the mechanism by which prions change their shape and
aggregate might be put to good use in biological systems. In back-to-back
papers in the December 26 issue of Cell, researchers ascribe prion-like
properties to an elegant mechanism involved in maintaining memory.

Susan Lindquist, director of the Massachusetts Institute of Technology's
Whitehead Institute, and Eric Kandel, professor of physiology and psychiatry
at Columbia University College of Physicians and Surgeons, describe a
protein, cytoplasmic polyadenylation element-binding protein (CPEB), which
appears to mark active synapses. The protein behaves like a prion in yeast
cultures, and its alternative self-perpetuating form-generally associated
with disease states for other prions-appears to be the protein's active
form.

Researchers, in looking to understand memory formation, have struggled to
comprehend how a neuron can strengthen specific synapses while leaving
others alone. Kandel, who shared the 2000 Nobel Prize for work on neuronal
signaling, has shown that protein synthesis, localized to the dendrites,
enables a function known as long-term facilitation, which is a strengthening
of synaptic connections in the large neurons of the sea slug Aplysia
californica.

In the Cell papers, he proposes that CPEB maintains that strengthening
process by spurring local translation of ubiquitous but dormant messages,
such as those for structural and regulatory molecules, which allow a synapse
to grow. "It takes sleeping messenger RNAs and it wakes them up," Kandel
told The Scientist.

Read the rest at The Scientist.com
http://www.biomedcentral.com/news/20031229/02

Posted by
Robert Karl Stonjek.
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