The effect of the Drosophila melanogaster Fhod tail on actin assembly

Formin-family proteins are a diverse group of proteins that accelerate actin nucleation and elongation. Understanding the dynamics and biochemical nature of proteins that assist in actin assembly can provide insight into normal development, as well as dystrophies, cardiomyopathies, and cancer. Formins are defined by their homodimeric Formin Homology (FH) 2 domain and proline-rich FH1 domain. The FH2 domain binds to the fast-growing barbed-end of actin filaments and the FH1 domain delivers profilin-bound actin to the FH2 domain, accelerating elongation. The Drosophila melanogaster Formin Homology Domain (Fhod) protein is important in muscle development, tracheal development and macrophage motility. We previously reported that Fhod isoform A nucleates, protects barbed-ends, and bundles actin filaments. Here, we show the analysis of constructs designed to characterize the variable C-terminal tail of Fhod. Formin tails alter both nucleation and elongation activity, and must be considered in conjunction with the FH1 and FH2 domains