Spectrin-like proteins in the paraflagellar rod structure of Trypanosoma brucei

A polyclonal, monospecific rabbit antibody to human erythrocyte spectrins cross-reacted with two sets of proteins (a doublet of 180/200K and a triplet of 67-66-65K; K = 10(3) Mr) in the parasitic protozoon Trypanosoma brucei brucei. Except for the 66K protein, the cross-reacting proteins are localized in the flagellum, on the basis of evidence from cell fractionation and immunofluorescence microscopy. Immunogold labelling and electron micrographs further revealed that the spectrin-like proteins are confined to the paraflagellar rod structure. The spectrin-like proteins with apparent molecular weights of 180 and 200 share homology with spectrin band 1, since V8-protease from Staphylococcus aureus generated similarly sized, antigenic peptides from these proteins. The results indicate homology between the cross-reacting proteins and human red cell spectrin.