Profilin controls two separate pathways in migrating cells’ actin network
CRISPR experiments showed that profilin regulates actin networks at the leading edge of migrating cells through two separable routes: it supports Arp2/3 localization while altering capping-protein effects through Ena/VASP. TU Braunschweig and Phys.org report the same cell study, while a mathematical model suggests Ena/VASP and capping protein compete for a shared recruitment mechanism. The result explains a mechanism of cell movement; it does not demonstrate a cancer or infection treatment.
Science··Midday
Division of labor at the leading edge
TU Braunschweig and Phys.org cover the same study of four actin regulators in the flat lamellipodia at the front of migrating cells. Using CRISPR in B16-F1 mouse melanoma cells, the researchers disrupted profilin 1, the Arp2/3 complex, capping protein and the Ena/VASP family alone and in combinations. Imaging then compared the consequences for actin-network assembly, leading-edge protrusion and cell migration. This design tested the regulators’ division of labor without equating loss of one protein with cell movement as a whole.[1], [2]
Profilin tunes two separable routes
Both reports converge on profilin supporting the Arp2/3-dependent branched network while countering Ena/VASP activity. Ena/VASP and capping protein also restrain one another. In combined gene disruptions, profilin still supported Arp2/3 localization at the leading edge when Ena/VASP was absent, whereas the effect of profilin loss on capping protein disappeared without Ena/VASP. That split shows profilin acting on Arp2/3 and capping protein through separable routes rather than through consecutive steps in one chain.[1], [2]
The model proposes a competition
A mathematical model fitted to the experimental data proposes that Ena/VASP and capping protein must compete for a shared recruitment mechanism at the lamellipodial edge. That recruitment site was not directly imaged; it is a model inference that jointly explains the cell experiments. The study identifies profilin as a central regulator of branched actin networks and offers a mechanism that may reconcile earlier conflicting results. The evidence remains limited to cultured mouse melanoma cells, with no intervention tested for reducing cancer spread or treating infection.[1], [2]
