TRYPANOSOMA-CRUZI - MONOCLONAL-ANTIBODY TO CYTOSKELETON RECOGNIZES GIANT PROTEINS OF THE FLAGELLAR ATTACHMENT ZONE

Cytoskeletal preparations of Trypanosoma cruzi trypomastigotes and epi mastigotes contain a protein recognized by a monoclonal antibody (2G4) which is connected to the flagellar attachment zone of both stages of the parasite. Western blot analysis revealed that the antibody was ab le to recognize protein bands of molecular masses higher than 700 kDa up to 2500 kDa. These giant proteins do not seem to share sequences wi th beta-connectin since an anti-beta-connectin antibody did not recogn ize the T, cruzi proteins nor did the 2G4 monoclonal antibody recogniz e authentic beta-connectin, Immunofluorescence and immunogold electron microscopy provided evidence that this protein is located inside the cell body of the parasite, closely related to a corset of four microtu bules known as subpellicular microtubule quartet. Immunogold labeling shows that the protein accompanies the flagellar attachment zone as lo ng as the flagellum adheres to the cell body. It is proposed that thes e microtubule-associated proteins recognized by the 2G4 monoclonal ant ibody exist only in trypanosomatid forms having a junctional complex b etween the flagellum and the cell body and may act as transmembrane el ements connecting the subpellicular microtubular quartet with the flag ellum at the desmosome region. (C) 1995 Academic Press, Inc.