title: A giant protein associated with the anterior pole of a trypanosomatid cell body skeleton.
abstract: A megadalton protein was found to be a cytoskeleton component of the promastigote forms of the flagellate Phytomonas serpens. This protein migrated on sodium dodecyl sulfate polyacrylamide gel electrophoresis as a doublet of polypeptides with a molecular mass similar to muscle beta-connectin (titin) 2500-3000 kDa. A polyclonal antibody raised against this protein reacts, by immunoblot analysis, with Phytomonas serpens and two others Phytomonas species. In addition, the Phytomonas serpens protein was immunoprecipitated after being metabolically labeled with [35S]methionine. This antibody did not cross-react with the cytoskeletal proteins of Trypanosoma cruzi, Crithidia luciliae thermophila, Crithidia fasciculata and Leptomonas samueli or with beta-connectin (titin). Indirect immunofluorescence microscopy analysis revealed a punctate fluorescence staining at the anterior region of the parasite's body skeleton. Moreover, immunogold electron microscopy of cytoskeletal preparations and of thin sections of whole cells indicates that the giant protein appears to cap the anterior end of the cell body microtubules at the level of the junctional complex. We suggest that this giant protein may serve as a linker between the cell body skeleton and the flagellum membrane.
authors.affiliation: Departamento de Parasitologia, Universidade de Säo Paulo, Brazil.
authors.forename: M M
authors.initials: MM
authors.lastname: Baqui
authors.forename: C S
authors.initials: CS
authors.lastname: Takata
authors.forename: R V
authors.initials: RV
authors.lastname: Milder
authors.forename: J
authors.initials: J
authors.lastname: Pudles
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003599:Cytoskeleton / Q000737:chemistry* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D008970:Molecular Weight; D011233:Precipitin Tests; D015800:Protozoan Proteins / Q000032:analysis / Q000302:isolation & purification; D014351:Trypanosomatina / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure
chemical_list: D015800:Protozoan Proteins