From Kurzweil AI:
Stanford School of Medicine scientists have mapped the 3D atomic structure of a two-part protein complex that controls the release of signaling chemicals, called neurotransmitters, from brain cells in less than one-thousandth of a second. The experiments were reported today (August 17) in the journal Nature. Performed at the Linac Coherent Light Source (LCLS) X-ray laser at the Department of Energy’s SLAC National Accelerator Laboratory, the experiments were built on decades of previous research at Stanford University, Stanford School of Medicine, and SLAC. “This is a very important, exciting advance that may open up possibilities for targeting new drugs to control neurotransmitter release,” said Axel Brunger, the study’s principal investigator — a professor at Stanford School of Medicine and SLAC and a Howard Hughes Medical Institute investigator. “Many mental disorders, including depression, schizophrenia and anxiety, affect neurotransmitter systems.” The two protein parts are known as neuronal SNAREs and synaptotagmin-1. “Both parts of this protein complex are essential,” Brunger said, “but until now it was unclear how its two pieces fit and work together.” Earlier X-ray studies, including experiments at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) nearly two decades ago, shed light on the structure of the SNARE complex, a helical protein bundle found in yeasts and mammals. SNAREs play a key role in the brain’s chemical signaling by joining, or “fusing,” little packets of neurotransmitters to the outer edges of neurons, where they are released and then dock with chemical receptors in another neuron to trigger a response.
Explains rapid triggering of brain signaling
In this latest research, the scientists found that when the SNAREs and synaptotagmin-1 join up, they act as an amplifier for a slight increase in calcium concentration, triggering a gunshot-like release of neurotransmitters from one neuron to another. They also learned that the proteins join together before they arrive at a neuron’s membrane, which helps to explain how they trigger brain signaling so rapidly. The team speculates that several of the joined protein complexes may group together and simultaneously interact with the same vesicle to efficiently trigger neurotransmitter release, an exciting area for further studies.