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The Nobel on Medicine rewards three specialists on the brain

. . . Paul Greengard has shown that all of the tasks accomplished inside the cell following a signal received at the cell membrane are controlled by signals that proteins address to themselves. These signals essentially consist in the addition (phosphorylation) or excision (dephosphorylation) of chemical groups (phosphates) . . . resulting in the modification of the spatial structure and function of these proteins. These chemical reactions are accelerated by enzymes (protein kinases and protein phosphatases), the discovery of which has been a great step in understanding the mechanisms responsible for the transmission of cellular signals.

“The brilliant contribution of Paul Greengard has been to show that this phosphorylation mechanism, which had previously been described, is universal and plays a fundamental role in the nervous system”, comments Jean-Antoine Giraud (College de France) who spent a few years in Paul Greengard's laboratory. In neurons that respond to dopamine, the transmission of nervous signals by phosphorylation–dephosphorylation cascades is regulated by a central protein, DARPP-32. Like the director of an orchestra, this protein controls the function of numerous other proteins, allowing for the modification of the excitability of rapid synapses, which function in an electrical rather than a chemical manner . . .