Is a Calpain-Like Protein Located at the Flagellum Attachment Zone

calpain-like cysteine peptidase family, comprising active calpains and calpain-like proteins, is addressed. Immunofluorescence analysis and biochemical fractionation were used to demonstrate the cellular location of H49 proteins. ancestor from other trypanosomatid lineages. Immunofluorescence and immunoblotting experiments demonstrated that H49/calpain is located along the flagellum attachment zone adjacent to the cell body.H49/calpain contains large central region composed of 68-amino acid repeats tandemly arranged. They can be classified as calpain-like proteins as the cysteine protease catalytic triad is partially conserved in these proteins. H49/calpains could have a structural role, namely that of ensuring that the cell body remains attached to the flagellum by connecting the subpellicular microtubule array to it