Researchers have identified a gene encoding a tandem potassium channel in a giant virus that infects marine algae. The discovery appears in Proceedings of the National Academy of Sciences.
Tandem potassium channels perform functions in human physiology by conducting potassium ions across cell membranes, helping to stabilize membrane potential and regulate nerve cell electrical excitability. They differ structurally from other potassium channels because two of their four pore-forming subunits are directly linked together.
Precursors of tandem potassium channels have not been found in bacteria, leaving questions about their evolutionary origins. The international team, including researchers from TU Darmstadt's Department of Biology and Bonn-Rhein-Sieg University of Applied Sciences' Department of Natural Sciences, examined the viral genome and conducted experiments on the gene.
"Our experiments show that this gene encodes a protein with the functional properties of a potassium channel," says Dr. Oliver Rauh, a scientist in the DFG research network "CytoTransport" at H-BRS.
The researchers examined evolutionary relationships between the newly discovered viral channel and known tandem potassium channels. Unlike most viral genes, which typically originate from host genetic material, this potassium channel gene appears to be of viral origin.
"This finding further reinforces a new perspective according to which the giant mimiviruses, to which this virus belongs, have played a central role in the evolution of proteins in higher organisms," says Gerhard Thiel, a professor in the Department of Biology at TU Darmstadt.
The same virus has yielded other proteins of interest. Other researchers previously discovered a light-controlled ion channel from this virus used in optogenetics, a field recognized with the Nobel Prize.