Tucked in the Swiss lakeside town of Kreuzlingen, researchers have just cracked open one of the body's most elegant cleaning mechanisms—and the discovery could reshape how we design drugs and understand why cancer spreads.
Scientists at the Institute of Cell Biology and Immunology Thurgau (BITG), an associated institute of the University of Konstanz, have decoded how a family of atypical chemokine receptors, particularly one called ACKR4, clears away chemical signals that immune cells no longer need. It's a seemingly small detail about cellular housekeeping, but it touches something vast: how immune cells find their way through the body, how inflammation gets controlled, and how cancer cells learn to migrate and metastasize.
The human body is constantly flooded with chemical signals. Immune cells need guidance to reach exactly the right tissues—infections don't announce themselves in one place, and neither do the body's healing processes. Chemical messengers called chemokines act like breadcrumbs, drawing immune cells toward sites of inflammation or injury. But once the job is done, those signals have to vanish. Otherwise, the immune system stays revved up, leading to chronic inflammation, autoimmune diseases, or worse: cancer cells exploit these same chemical highways to slip into lymphoid organs and establish distant tumors.
Enter ACKR4 and its cousins in the atypical chemokine receptor family. These proteins do something remarkable: they pluck excess chemokines from tissue and drag them inside the cell for destruction, essentially hitting the reset button on the immune landscape. "It is via these atypical receptors that tissue cells take superfluous chemokines inside the cell for degradation," the research explains. They're not just cleaning up—they're also shaping the gradients of chemical signals that guide immune cells in the first place.
What the BITG team, led by Professor Daniel Legler and first author Oliver Gerken, discovered was previously unknown. ACKR4 doesn't simply sit on the cell surface waiting for chemokines. Instead, it continuously shuttles back and forth between the cell membrane and internal organelles like a molecular commuter. Every time it surfaces, it grabs a chemokine, pulls it inside, and delivers it to be broken down. "Every time the receptor reaches the cell's surface, it binds a chemokine and takes it along into the cell where it is degraded," Legler explains.
The team also identified the signaling proteins that work with ACKR4 to speed up this uptake process, and they revealed that the signal transduction pathways don't follow the rules scientists thought governed these receptors. This wasn't dogma confirming itself—it was dogma being rewritten. The findings, published in Nature Communications, expose a mechanism that remained hidden until now.
Why does this matter beyond the ivory tower? G protein-coupled receptors, the family that includes both chemokine receptors and ACKR4, are targets for roughly one-third of all drugs on the market. Better understanding how these receptors work means better drugs with fewer side effects, and it means new angles for treating diseases where abnormal cell migration goes wrong. For cancer researchers studying how tumors spread, and for immunologists fighting chronic inflammation, this work opens doors that were previously locked. The foundation is now laid for deeper research into the complex mechanisms of these receptors—and the body's other elegant solutions hidden just inside the cell membrane.