Figure 8. Model summarizing FMNL2/3 loss of function phenotype.

Lamellipodial actin filament networks are generated and turned over by combined activities of filament assembly factors (Arp2/3 complex and formins), disassembly factors such as cofilin and by capping protein. As opposed to the branching activity of Arp2/3 complex, lamellipodial formins FMNL2 and FMNL3 are not essential for the generation of lamellipodial actin networks, but proposed to generate specific subsets of filaments contributing to the density and mechanical stability of lamellipodia, essential for effective protrusion and lamellipodial force generation (FMNL2/3 KO) during migration.