( Neurobiologists have gained new insight...)How the neuron sprouts its branches

Such basic insights into neuronal growth will help researchers better understand brain development in children, as well as aid efforts to restore neuronal connections lost to injury, stroke or neurodegenerative disease, said the researchers.

In a paper published in the Dec. 8, 2005, issue of Neuron, Howard Hughes Medical Institute investigator Michael Ehlers and his colleagues reported that structures called "Golgi outposts" play a central role as distribution points for proteins that form the building blocks of the growing dendrites.

Besides Ehlers, who is at Duke University Medical Center, other co-authors were April Horton in Ehlers' laboratory; Richard Weinberg of the University of North Carolina at Chapel Hill.; Bence Rácz in Weinberg's laboratory; and Eric Monson and Anna Lin of Duke's Department of Physics. The research was sponsored by The National Institutes of Health.

The Golgi apparatus is a cellular warehouse responsible for receiving, sorting and shipping cargoes of newly synthesized molecules needed for cell growth and function. Until the new findings, researchers believed that only a central Golgi apparatus played a role in such distribution, said Ehlers.

"In most mammalian cells, the Golgi has a very stereotyped structure, a stacked system that resides near the cell nucleus in the middle of the cell," he said. "But mammalian neurons in the brain are huge, with a surface area about ten thousand times that of the average cell. So, it was an entirely open question where all the membrane components came from to generate the complex surface of growing dendrites. And we thought these remote structures we had
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Source:Duke University Medical Center