Fig. 5.

Model of nucleation and elongation of Sca2. The N- and C-terminal domains of Sca2 interact and might give rise to an FH2-like processive cap at the barbed end of the actin filament for elongation. Prorich regions adjacent to these domains mediate the incorporation of profilin-actin complexes. The WH2 domains recruit actin monomers for efficient nucleation. A detailed account of the experimental evidence leading to this model is shown in Fig. S10.