Fig. 6: Model of DRF activation of actin polymerization.

A Mechanism of DIAPH1-RhoA localization and activation (i-viii). Color scheme of the DIAPH1 domains is as in Fig. 1A. RhoA-GDP is pink and RhoA-GTP is purple. To localize at the membrane RhoA is farnasylated and unphosphorylated. Other cytoskeleton remodeling proteins, such as profilin, cofilin1/ADF, or cross-linkers that contribute to the described mechanism are omitted for clarity; their roles in this model are a subject for future investigations. B Three-dimensional plot showing K_d^D/R as a function of α and [RhoGTPase] for DRFs. α and [RhoGTPase] are on a logarithmic scale. The line represents α = 1 and has zero curvature in the [RhoGTPase] dimension. The plot was constructed using K_d^D and K_d^R derived from the RhoA-DIAPH1 interaction. Derivations are in Supplementary Appendix 1. C Three-dimensional plot of unbound DAD, 1-F_DB, as a function of RhoGTPase concentration and [DAD]_eff. [DAD]_eff and [RhoGTPase] are on a logarithmic scale. The gradient from deep blue to yellow shows increasing DIAPH1 activation. Derivations are in Supplementary Appendix 5. The plot was constructed using K_d^R, K_d^D and α derived from the RhoA-DIAPH1 interaction.