Cells Reorganize Their Actin Skeleton Normally Without Coronin Proteins, Study Finds

For decades, coronins — proteins found across the animal kingdom, from single-celled amoebae to humans — have been described in textbooks as regulators of the actin cytoskeleton, the network of filaments that gives cells their shape and lets them move. A new study led by Professor Jean Pieters at the Biozentrum, University of Basel, published in PLOS Biology, challenges that view, reporting that coronins are largely dispensable for the overall organization of the actin cytoskeleton.

"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," Pieters said, noting that cells lacking coronins continued to organize and remodel their actin networks normally. The researchers examined native, untagged coronins using a broad range of experimental approaches.

One striking result concerned a common laboratory technique: attaching a molecular tag to a protein to track it inside cells, a method usually assumed not to affect the protein's function. First author Roko Gvozdenica found that tagging coronin proteins could cause them to lose function and change location within the cell. The team also found that many antibodies commonly used to detect coronins lack specificity, adding to broader concerns about antibody reliability in biomedical research.

The findings do not rule out an indirect connection between coronins and the cytoskeleton, and the researchers confirmed a separate, established role for coronins in cell signaling — including a role that is essential for maintaining normal T cell numbers, which is vital for protecting the body against infection or cancer. Pieters said the study may open new avenues for understanding how coronins are involved in cell signaling more broadly.