Ijeoma Asilebo (University of Notre Dame)

In the 2025 publication in Nature Communications, the authors describe “OptoVCA,” a novel in vitro optogenetic system that enables precise control over the assembly of branched actin networks on lipid membranes. The OptoVCA tool uses light to regulate Arp2/3 complex activity, allowing fine adjustment of network density, thickness, and architecture by varying illumination power, duration, and spatial pattern. Using this system, the authors investigate how actin network density shapes the behavior of two key actin-binding proteins, myosin and ADF/cofilin. They show that network density selectively regulates protein behavior, with increased density limiting myosin penetration but enabling directional flow where penetration occurs, while ADF/cofilin can still access dense networks yet becomes less effective at promoting disassembly. Together, these findings demonstrate that actin network density is a powerful and selective regulator of protein activity and dynamics. This work highlights the potential of optogenetic control to dissect cytoskeletal mechanics with high precision and provides new insight into how the physical properties of actin networks contribute to cellular function.

References
Yamamoto, K.; Miyazaki, M. Optogenetic actin network assembly on lipid bilayer uncovers the network density-dependent functions of actin-binding proteins. Nat. Commun. 2025, 16, 7583. DOI: 10.1038/s41467-025-62653-6.