Figure 2.

Phylogenetic analysis of the importin α family. (A) Phylogenetic trees generated using the KPNA protein sequences from human, D. melanogaster (fly), and S. cerevisiae (Yeast). The three subfamilies are shaded in green (a1 subfamily), blue (a2 subfamily) and yellow (a3 subfamily). Phylogenetic trees were also generated using the ARM repeat domains and the IBB domains. Scales bar is 0.1 branch length. of the human importin a family. The sole S. cerevisiae importin α, SRP1 (Yeast KPNA), is included as a common ancestor. D. melanogaster contains one member each of the α1, α2, and α3 subfamilies, which are included (Fly KPNA) to define the subfamilies. The phylogenetic trees labeled ARM repeats and IBB were generated using either the ARM repeat or IBB domains of all 7 human KPNA proteins. (B) Comparison of the divergence of the IBB and ARM repeat domains of the human KPNA proteins from the same domains in Yeast SRP1. Divergence was measured as branch length of the phylogenetic trees from SRP1 to the given domain of each KPNA.