RICHMOND, Va. (Sept. 18, 2008) Virginia Commonwealth University School of Medicine researchers have uncovered how sodium is able to control specific potassium ion channels in cells, according to new study findings published online this week in Nature Chemical Biology.
These findings, published Sept. 14, may help researchers gain a greater understanding of the mechanisms involved in ion channel gating and may one day set the stage for new approaches in drug design.
Intracellular-sodium is known to control the opening and closing of certain potassium channels. Using a computational-experimental approach, researchers examined the interaction between sodium and a group of potassium channels known as Kir channel proteins. The team had previously shown that Kir3 channels are sensitive to sodium, but had not shown how sodium is coordinated by specific amino acids found in several Kir channel proteins.
"We have a fairly good molecular understanding of how the sodium ions are coordinated and we have a compelling hypothesis of how the coordination of sodium may be affecting this particular type of potassium ion channel to open it," said Diomedes Logothetis, Ph.D., an internationally recognized leader in the study of ion channels and chair of the VCU School of Medicine's Department of Physiology and Biophysics.
According to Logothetis, ion channel proteins are found in the plasma membrane of cells and provide a path for hydrated cations such as calcium, potassium or sodium to pass through the membrane and travel in and out of the cell. Generally, hydrated ions do not travel through the lypophillic, or fat-based, plasma membrane because they are surrounded with water and require a pathway to travel from one side of the membrane to the other.
"By applying the knowledge of the sodium coordination site, we identified the Kir5.1 channel that was not previously suspected to be sodium-sensitive. By examining in which cells t
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Virginia Commonwealth University