Participation of actin in cellular processes relies on the dynamics of filament assembly. Filament elongation is fed by monomeric actin in complex with either profilin or a Wiscott-Aldrich syndrome protein (WASP) homology domain 2 (WH2)/β-thymosin (βT) domain. WH2/βT motif repetition (typified by ciboulot) or combination with nonrelated domains (as found in N-WASP) results in proteins that yield their actin to filament elongation. Here, we report the crystal structures of actin bound hybrid proteins, constructed between gelsolin and WH2/βT domains from ciboulot or N-WASP. We observe the C-terminal half of ciboulot domain 2 bound to actin. In solution, we show that cibolout domains 2 and 3 bind to both G- and F-actin, and that whole ciboulot forms a complex with two actin monomers. In contrast, the analogous portion of N-WASP WH2 domain 2 is detached from actin, indicating that the C-terminal halves of the βT and WH2 motifs are not functionally analogous. ©2006 Elsevier Ltd. All rights reserved.
Aguda, A. H., Xue, B., Irobi, E., Préat, T., & Robinson, R. C. (2006). The structural basis of actin interaction with multiple WH2/β-thymosin motif-containing proteins. Structure, 14(3), 469–476. https://doi.org/10.1016/j.str.2005.12.011