"Molecular dance" – key mechanism of cell movement finally decoded, offering new insights into cancer research

Inside every cell, a delicate network of protein filaments known as the cytoskeleton provides structure and stability. Actin filaments play a crucial role in this system – these tiny protein strands are continuously assembled and disassembled to enable movement. Until now, however, the exact process behind their breakdown has remained unclear.

A research team from the Max Planck Institute, led by structural biologist Stefan Raunser, has discovered that three proteins – coronin, cofilin and AIP1 – work together in perfect harmony. The researchers describe this interaction as a “molecular dance,” with each protein playing a distinct role. Their findings were published in Cell in October 2025.

First, coronin binds to the filament and subtly alters its structure, making it easier for chemical changes – specifically the removal of phosphate groups – to occur. This step “matures” the filament, preparing it for the next phase. Cofilin then takes over, displacing coronin and further weakening the filament’s structure. Finally, AIP1 steps in. Acting like molecular pincers, this protein pulls the destabilized filament apart and prevents it from being rebuilt.

Ice and electricity reveal the cell’s dance

To unravel this process, the team used advanced cryo-electron microscopy. This technique involves rapidly freezing the proteins and imaging them with electron beams to generate highly detailed 3D structures. In total, the researchers captured more than a million individual images and reconstructed 16 snapshots that together reveal the complete sequence of events.

The result is a new, comprehensive model of filament degradation that challenges long-standing assumptions. For years, cofilin was believed to be the main protein responsible for cutting the filaments. In reality, however, this role belongs to AIP1. The study provides fresh insights into the fundamental mechanics of cell movement.

Implications for medicine and research

These findings are not only important for basic research. Cell movement also plays a key role in diseases such as cancer and in the immune response. In particular, during metastasis – the spread of cancer cells throughout the body – tumor cells exploit mechanisms similar to those used by healthy cells during wound healing.

Now that researchers understand how proteins such as AIP1, cofilin and coronin regulate cell movement, new opportunities may emerge to target these processes. In the long term, this knowledge could help develop therapies that slow down or even prevent the spread of cancer cells by interfering with their ability to move.