Fig. 1. Phylogenetic tree of the Pak family. (A) Pak subfamilies. In worms, flies and mammals, Paks fall into two structurally and functionally distinct groups, here termed A (green) and B (blue). Both budding and fission yeast contain an evolutionarily related group of Paks that contain a PH domain at the N-terminus (PH Paks; purple). The three Paks from slime mold form a separate group (yellow), as do the remaining Paks from budding and fission yeast (orange). Ce, Caenorhabditis elegans; Ds, Dictyostelium discoideum; Hs, Homo sapiens; Mm, Mus musculus; Sc, Saccharomyces cerevisiae; Sp, Schizosaccharomyces pombe. (B) Domain structure of Paks. One representative of each Pak subfamily is shown.