Fig. 8. Phylogenetic relationships of selected calpains from arthropods, nematode and human. The deduced amino acid sequences of the catalytic (II) and C₂-like (III) domains in land crab (Gl-CalpM, Gl-CalpB and Gl-CalpT), lobster (Ha-CalpM), fruit fly (Dm-CalpA and Dm-CalpB), nematode (TRA-3) and human (Capn1, Capn3 and Capn5) calpains were analyzed using ClustalW and Treeview software (see Materials and methods). The calpains cluster into four groups: T-type calpains (TRA-3, Gl-CalpT and Capn5), mammalian `typical' calpains (Capn1 and Capn3), crustacean M-type calpains (Gl-CalpM and Ha-CalpM) and arthropod A/B-type calpains (Gl-CalpB, Dm-CalpA and Dm-CalpB).