In populating the growing brain, neural stem cells must strike a delicate balance between two key processes – proliferation, in which the cells multiply to provide plenty of starting materials – and differentiation, in which those materials evolve into functioning neurons. If the stem cells proliferate too much, they could grow out of control and produce a tumor. If they proliferate too little, there may not be enough cells to become the billions of neurons of the brain. In a study appearing in journal Nature Neuroscience, Dr. William Snider and his lab have now found that this critical balance rests in large part on activity of a single kinase, called GSK-3.
The finding suggests that GSK-3 controls the signals that determine how many neurons actually end up composing the brain. It also has important implications for patients with neuropsychiatric illness, as links have recently been drawn between GSK-3 and schizophrenia, depression and bipolar disorder.