This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In the early 1980s, scientists observed an anomaly. Embedded within cell membranes, they identified ion channels with extraordinarily high conductance.
These so-called "BK" (Big K, or Big Potassium) channels had roughly 10 times the unitary conductance (i.e., conductance per individual channel molecule) of other potassium channels, enabling much more efficient, rapid transport of potassium ions. And while later structural characterization explained how this happened, no one could understand why. Published in Communications Biology, new research from the Okinawa Institute of Science and Technology (OIST) has shed light on the evolutionary origins of these powerful potassium conduits.
Through molecular simulation and evolutionary modeling, the researchers explored neuronal BK channel conductance across species and identified its effect on spike timing as a probable evolutionary pressure in the channel's development. Erik De Schutter, head of OIST's Computational Neuroscience Unit and an author of the study, comments, "BK channels are widely present across different neurons and known to be essential in regulating cell firing, the process in which electrical signals (spikes) coordinate communication between brain cells. "Despite their importance, no one really knew why we had developed these extraordinarily high-conductance channels.
Our work provides a possible answer to this longstanding mystery." Achieving even the simplest of tasks, like reading this sentence, relies on a complex jumble of neurons. Different cells and areas within the brain are involved in different data storage and processing tasks, and the whole system depends on careful intercellular communication. Electrical signals are responsible for coordinating this communication, triggering the release of chemical neurotransmitters.
These electrical signals are generated by charge changes at the cell membrane due to the movement of positively charged ions, which move through dedicated ion channels. While many ion channels exist, BK channels are particularly interesting to neuroscientists because of their high conductance, a measure that indicates how easily ions can pass through the channel. Across the animal kingdom, BK channels show significantly higher unitary conductance than other types of potassium ion channels, sometimes 10–20 times as high.
"However, channel conductance isn't universal across species," adds De Schutter. "It's extremely high in mammals or birds compared to invertebrates. We wanted to understand why." To explore these differences, De Schutter and his lab members enlisted the help of evolutionary biologists Thomas Bourguignon and Dr.
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