Cross-linking molecules modify composite actin networks independently

While cells make use of many actin binding proteins (ABPs) simultaneously to tailor the mechanical properties of the cytoskeleton, the detailed interplay of different ABPs is not understood. By a combination of macrorheological measurements and confocal microscopy, we show that the ABPs fascin and filamin modify the structural and viscoelastic properties of composite invitro actin networks independently. The outnumbering ABP dictates the local network structure and therefore also dominates the macromechanical network response.