(Sacramento, Calif.) -- UC Davis researchers have discovered that proteins that regulate brain-cell activity by controlling the flow of potassium ions behave more like volume controls on stereos rather than on/off power switches. The research, which appears in the 19 August issue of Science, provides a new model for the behavior of critical gatekeeper proteins found in neuronal membranes.
"We've shown that brains cells regulate activity in an incremental way, with thousands of different possible levels of activity," explained James Trimmer, senior author of the paper and professor of medical pharmacology and toxicology at UC Davis School of Medicine. He and his colleagues studied an ion channel that controls neuronal activity called Kv2.1, a type of voltage-gated potassium channel that is found in every neuron of the nervous system.
"Our work showed that this channel can exist in millions of different functional states, giving the cell the ability to dial its activity up or down depending on the what's going on in the external environment," said Trimmer. This regulatory phenomenon is called 'homeostatic plasticity' and it refers, in this case, to the channel protein's ability to change its function in order to maintain optimal electrical activity in the neuron in the face of large changes within the brain or the animal's environment. "It's an elegant feedback system," he added.
For years, scientists have attempted to study how neurons regulate the function of potassium ion channels -- pore-like openings in cell membranes that control the flow of potassium ions into the cell -- with limited success. The current study is the first to combine mass spectrometry-based proteomics and ion channel biophysics to the study of living brain cells. "This is an important biological question that couldn't have been answered any other way," Trimmer said.
Most cells in the body can get by with on/off-like switches, allowing them grow
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Contact: Carole Gan
carole.gan@ucdmc.ucdavis.edu
916-734-9047
University of California, Davis - Health System
17-Aug-2006