TbBILBO1 domains: (A) The TbBILBO1 protein consists of 587 amino acids, with a ubuquitin-like N-terminal domain (NTD, that ranges from amino acids 1–110), two EF-hand calcium-binding domains (EFH1 and EFH2, that ranges from amino acids 185–249), a long predicted CC domain and a leucine zipper (LZ, ranging from amino acids 533–578). The mutations in the EF-hand calcium binding domains are indicated below the wild-type amino acid sequence. Mutation studies have shown that the EF-hand domains modulate the morphology of polymers formed by TbBILBO1; (B) The main truncations used to characterize polymer formation capacities are shown schematically below the secondary structure and labeled as truncation (T), from T1–T4.