Last Updated on July 4, 2026 by Staff
Scientists have found out how small changes in acidity can control the movement of calcium inside cells through a molecular gate. The study, published in the Proceedings of the National Academy of Sciences (PNAS) shows that two tiny molecular clasps work together to regulate calcium flow in response to acidity.
The findings help us understand how cells communicate, respond to stress and maintain their functions. Researchers think the discovery could eventually help explain diseases linked to calcium imbalance and inspire treatments targeting similar proteins in humans.
Why Calcium Matters
Most people know calcium as the mineral that keeps bones and teeth strong. However inside living cells calcium plays a bigger role. Calcium acts as a signaling molecule that helps cells communicate, grow, move, repair damage and even decide whether to survive or die.
Because calcium controls many vital processes cells must carefully regulate how much calcium enters and leaves. Little calcium can weaken important biological signals while too much calcium can damage cells and trigger harmful stress responses.
To understand this regulation scientists focused on a protein called BsYetJ, a calcium leak channel found in the bacterium Bacillus subtilis. Although it comes from bacteria this protein belongs to a family of membrane proteins closely related to those found in humans making it an excellent model for studying calcium regulation.
Acidity Controls the Gate
The researchers wanted to know how acidity influences calcium movement through it.
Using membranes they observed individual protein channels opening and closing in real time. Their experiments revealed that when the environment became more acidic the channel opened frequently and allowed larger amounts of calcium to flow through.
Further investigation showed that this process depends on protons. The positively charged particles responsible for acidity.
Operating like a simple on-off switch, BsYetJ responds to increasing proton levels by changing its structure. This transformation allows calcium ions to pass easily through the membrane.
The discovery demonstrates how even slight changes in acidity can significantly influence communication.
Two Tiny Clasps
One of the discoveries was that the calcium channel is controlled by two separate molecular salt bridges described by researchers as tiny electrostatic clasps.
The first clasp functions like a latch. When protons weaken this connection, part of it shifts position increasing the likelihood that the channel opens. This clasp mainly controls how calcium is allowed to enter.
The second clasp performs a different task. By opening the channel it changes the electrical environment inside the pathway where calcium travels.
This adjustment determines how easily calcium ions can pass once the channel is already open.
Together these two clasps create a two-step control system. One regulates the opening of the gate while the other regulates the speed of calcium flow.
Watching Molecules Move
To observe these changes researchers used an advanced technique known as double electron–electron resonance spectroscopy (DEER).
This technology measures small changes in distance inside proteins allowing scientists to track structural movements at the nanometer scale.
The experiments showed that when acidity weakens the molecular clasp, one section of BsYetJ shifts position. Researchers combined these measurements with computer simulations to build three-dimensional models of both the closed and open forms of the channel.
The models revealed a tunnel running through BsYetJ that serves as the pathway for calcium ions.
Scientists then moved beyond membranes by inserting BsYetJ into living mammalian cells using tiny membrane structures called nanodiscs.
Remarkably the same two-clasp mechanism worked inside living cells confirming that the process is biologically relevant than simply an experimental observation.
Future Possibilities
Although the study focused on a protein its importance extends much further.
*BsYetJ belongs to the TMBAM family of proteins, whose human counterparts help regulate calcium balance and cellular stress responses. Many diseases, including disorders and certain forms of cancer are linked to disruptions in calcium signaling.
Researchers believe the discovered mechanism may represent a fundamental principle that has been preserved throughout evolution.
By relying on complex biological machinery, cells use simple chemical forces. Such as proton concentration and electrical attraction. To control essential life processes.
Understanding how these tiny molecular clasps regulate calcium could eventually help scientists design drugs that target pathways in human cells.
The research also highlights the efficiency of biology. A pair of salt bridges invisible to the naked eye work together like a finely tuned gatekeeper deciding not only when calcium enters a cell but also how much calcium flows through.
This discovery provides insight into one of the most fundamental communication systems in biology and opens new opportunities for future research, into cell signaling, disease mechanisms and precision medicine.