Enzyme governs nerve polarity

Two research groups in Asia have identified an enzyme that governs whether a neural projection becomes an axon or a dendrite and several of its upstream and downstream targets. Their findings on the function glycogen synthase kinase-3β (GSK-3β) were reported in the January 14 issue of Cell.

In the first paper, scientists from the Shanghai Institutes of Biological Sciences and the National Institute of Biological Sciences in Beijing, led by Yi Rao, reported that GSK-3β activity is inversely related to axon growth.

Rao, now the associate director of Northwestern University's Institute for Neuroscience, Chicago, told The Scientist, "The protein level is actually uniform [throughout the neuron]; but the activity of GSK is higher in dendrites than in axons. In a simple way, you could say that it is preferentially inactivated in axons."

To test the enzyme's role in establishing neural polarity, the researchers created constitutively active GSK-3β mutant rat hippocampal ...