Fig. 4. Sequence analysis of the three C. elegans p21-activated kinases. (A) An amino acid sequence comparison of the kinase domains from the three C. elegans PAKs and representative PAKs from other species. The asterisk indicates the site of the max-2(cy2) mutation. (B) A diagram of the structural organization of the three C. elegans PAKs. The red boxes indicate the P21-binding domain, the blue box indicates the site of a clearly conserved autoinhibitory domain, the green ovals indicate the kinase domain and the vertical lines indicate the sites of putative SH3-interacting (PXXP) domains. (C) An unrooted phylogenetic tree of the entire amino acid sequence of all the known PAKs from C. elegans (Ce), D. melanogaster (Dm) and H. sapiens (Hs). The group I/A and group II/B PAKs are boxed with blue and green, respectively. This tree was generated with the ClustalW alignment tool from the European Bioinformatics Institute (www.ebi.ac.uk/clustalw/). Sequences for max-2 and pak-2 were deposited in GenBank as DQ523832 and DQ523831, respectively.