Scientific progress comes not only from discovering something entirely new, but also from taking a fresh look at long-held assumptions. Now, a team at the University of Basel, Switzerland, challenges the decades-old view that coronin proteins primarily regulate the cytoskeleton.

Coronins are found throughout the animal kingdom, from single-celled amoebae to humans, and are involved in many vital processes including immunity, development and cell survival. For decades, textbooks and hundreds of scientific papers have described coronins primarily as proteins that bind to actin, a key component of the cytoskeleton.

Because of this presumed interaction, coronins have long been primarily regarded as regulators of the cytoskeleton – a network of actin filaments that gives cells their shape, enables them to move and helps organize their contents. But in a new study published in "PLOS Biology", researchers led by Professor Jean Pieters at the Biozentrum of University of Basel challenge this widely accepted view, finding coronins to largely be dispensable for the organization of the actin cytoskeleton overall, while demonstrating additional roles for the coronin protein family.

Revisiting decades-old assumptions

In the current study, the researchers comprehensively examined native coronins using a broad range of experimental approaches.

Over the years, my laboratory failed to find evidence for a direct role of coronin proteins in actin binding and modulation across a wide range of model systems. Even cells lacking coronins continue to organize and remodel their actin networks normally. Of course, absence of evidence is not evidence of absence."

Professor Jean Pieters, Biozentrum of University of Basel

One of the study's most striking results concerns a tool routinely used in biological research. To visualize and track proteins inside cells, scientists often modify their protein of interest with a molecular tag.

"These tags are extremely useful and assumed to be innocuous for protein function," says Roko Gvozdenica, the study's first author. "However, we found that the tagging of coronin proteins has the potential to cause loss of their function and significantly alter their localization."

The researchers assume that at least some of the evidence linking coronins to actin may be plagued by experimental artefacts. They also found that many antibodies commonly used to detect coronins lack specificity, reinforcing broader concerns about antibody reliability across biomedical research.

Role of coronins in cell signaling

The researchers point to another function of coronins. "Over the years, we have reported that coronins are involved in cell signaling" emphasizes Pieters. "In the immune system, for example, coronin involvement in these signaling processes was found to be essential for the maintenance of normal T cell numbers, which is vital for protecting the body against infections or cancer."

Although the findings challenge a widely accepted model, they do not rule out a connection between coronins and the cytoskeleton. In fact, coronins may influence how cells organize their cytoskeleton both directly and indirectly through their signaling roles. By revisiting assumptions that have shaped the field for decades, the study may open new avenues for understanding the roles of coronin proteins in signal transduction, including in the ability of cells to communicate, survive and maintain the delicate balance in cell numbers.

Source:

Journal reference:

Gvozdenica Šipić, R., et al. (2026). Reassessment of the roles of coronin proteins as actin effectors and in signaling. PLOS Biology. DOI: 10.1371/journal.pbio.3003904. https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003904