MADISON University of Wisconsin-Madison researchers have solved the mystery surrounding a "rogue protein" that plays a role in the release of neurotransmitters and hormones in the brain.
The scientists found abundant amounts of the puzzling protein whose main location and function were unknown until now in a specific area of the pituitary gland. Like someone at a control knob, the protein may adjust the release of the two hormones that come almost exclusively from the posterior pituitary: oxytocin, which controls many reproductive functions, and vasopressin, which controls fluid balance.
"The findings raise very interesting possibilities for women's health, in which rising and falling hormone levels play a key role in many biological processes," says senior author Meyer Jackson, a professor of physiology at the UW-Madison School of Medicine and Public Health (SMPH). More studies will be needed to better understand the protein, he adds.
The study appears in the Jan. 11 Nature Neuroscience.
The research focused on Syt IV, a maverick member of the synaptotagmin family of 17 proteins, which are present in both mice and humans. Synaptotagmins are usually embedded in the membranes of small sacs, or vesicles, filled with neurotransmitters and hormones within nerve terminals. When an electrical impulse from one cell reaches a nerve terminal, it triggers the release of calcium, which in turn triggers the spilling out of the vesicle's contents neurotransmitters and hormones so they can act on other cells.
"Most synaptotagmins are triggering molecules that drive a vesicle's membrane into the membrane that surrounds a neighboring cell so that chemicals inside the vesicle can come out," says Jackson.
But Syt IV is an odd member of the family because it doesn't bind to calcium, said Jackson. In addition, Syt IV is found only sparsely in most parts of the brain. But Jackson and his colleagues were surprise
|Contact: Dian Land|
University of Wisconsin-Madison