Chemists at the University of Massachusetts Amherst have revealed a surprising “leakiness” in big potassium (BK) channels – crucial components of the body’s electrical system – potentially reshaping our understanding of cellular communication. Building on their 2018 work, the team demonstrated that these channels, responsible for ion flow in neurons and cardiac tissue, aren’t fully capable of stopping electrical signals, despite appearing closed. “We’ve discovered that this vapor barrier is inherently leaky, determined by the laws of physics,” explains UMass Amherst Professor of Chemistry Jianhan Chen, meaning ions can always slip through, albeit with a small probability. This discovery, published recently in PRX Life, offers a new avenue for investigating malfunctions like epilepsy and hypertension linked to these vital channels.
Hydrophobic Pore Creates Vapor Barrier in BK Channels
Instead of traditional on/off switches, BK channels utilize a soft gate dependent on water repellency, influencing the body’s electrical signaling. The research demonstrates that the pore of the BK channel is “very hydrophobic, or water-repellent,” and when constricted, expels water, forming a barrier that impedes potassium ion movement. This isn’t a complete shutoff, however; the team discovered the barrier is “intrinsically open,” allowing a small probability of ions to pass through. Chen illustrates the concept with a simple analogy: “If you drip a drop of water on [wax paper], it doesn’t absorb but beads up into a droplet.
Now roll that wax paper into a tube…and you have a BK channel’s pore.” Because ions are always hydrated, excluding water effectively blocks their flow, though not entirely. This inherent leakiness, determined by “the laws of physics,” offers a novel avenue for studying channel function and potential malfunctions linked to conditions like epilepsy and hypertension.
2018 Research Establishes Unique BK Channel Property
Unlike many ion channels possessing definitive on/off mechanisms, BK channels—crucial for the electrical signaling in neurons and cardiac tissue—don’t fully close, presenting a long-standing puzzle for scientists. The team’s work, published in PRX Life, revealed that this persistent, low-level activity isn’t a flaw, but an inherent property dictated by the channel’s unique physical structure. “In 2018, we showed that BK channels have a unique property,” explains Jianhan Chen, Professor of Chemistry at UMass Amherst. The key lies in the channel’s pore, which Chen describes as “very hydrophobic, or water-repellent.” This hydrophobicity creates a vapor barrier, effectively restricting ion flow when the channel narrows, but never completely eliminating it.
Inherent “Leakiness” Dictates Ion Flow Regulation
Building on their 2018 findings, the team, led by Jianhan Chen, Professor of Chemistry, has revealed a fundamental characteristic of these channels: inherent leakiness. This isn’t a failure of the system, but rather a consequence of the physical properties governing ion flow, and offers a new lens through which to study the body’s electrical infrastructure. The team discovered that while BK channels possess a hydrophobic pore designed to restrict ion passage, complete blockage is impossible. This “soft gate,” as the researchers term it, functions similarly to wax paper; while it repels water and can narrow to impede flow, it cannot achieve absolute impermeability. The research, recently published in PRX Life, was supported by the National Institutes of Health.
We’ve discovered that this vapor barrier is inherently leaky, determined by the laws of physics.
