title: The ubiquitin-ligase system in Trypanosoma brucei brucei.
abstract: The question of whether the African trypanosome Trypanosoma brucei brucei utilizes a ubiquitin-ligase system to conjugate the 8,500-dalton protein ubiquitin to other proteins has not been investigated. Using 125I-labeled ubiquitin and gel electrophoresis (sodium dodecyl sulfate and acetic acid, urea, Triton X-100), we looked for the incorporation of label into proteins larger than ubiquitin to determine ubiquitin-ligase system activity in cytosolic and nuclear lysates of long slender, intermediate, and short stumpy bloodstream-form trypanosomes. We present data suggesting that there is cytosolic activity of a ubiquitin-ligase system in all three bloodstream forms of T. brucei brucei. There are indications that the three bloodstream forms of T. brucei brucei differ in their cytosolic ubiquitin-ligase system activity. Our assay showed no activity of this system in the nucleus of T. brucei brucei. Further studies on the ubiquitin-ligase system in T. brucei brucei may define differences between the three bloodstream forms, the parasite, and its host, leading to development of novel chemotherapeutic strategies.
authors.affiliation: Department of Biology, University of Dayton, Ohio.
authors.forename: D J
authors.initials: DJ
authors.lastname: Lowrie
authors.forename: B F
authors.initials: BF
authors.lastname: Giffin
authors.forename: R M
authors.initials: RM
authors.lastname: Ventullo
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003600:Cytosol / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D008025:Ligases / Q000032:analysis*; D015800:Protozoan Proteins / Q000378:metabolism; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000648:ultrastructure; D044767:Ubiquitin-Protein Ligases; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: D015800:Protozoan Proteins; D014452:Ubiquitins; D044767:Ubiquitin-Protein Ligases; D008025:Ligases