A maximum likelihood tree of actin-related proteins. The root position was forced between the HSP70 superfamily and the actin superfamily. The tree was constructed by analysis of 295 aligned amino acid residues (Additional File 8). Support values are indicated only for major internal branches (not within smaller monophyletic groups). The protein sequences whose structure alignment was used to correct the multiple protein alignment of actin-related proteins are denoted in red. For the complete legend, see Additional File 5.