title: Analysis of proteasomal proteolysis during the in vitro metacyclogenesis of Trypanosoma cruzi.
abstract: Proteasomes are large protein complexes, whose main function is to degrade unnecessary or damaged proteins. The inhibition of proteasome activity in Trypanosoma cruzi blocks parasite replication and cellular differentiation. We demonstrate that proteasome-dependent proteolysis occurs during the cellular differentiation of T. cruzi from replicative non-infectious epimastigotes to non-replicative and infectious trypomastigotes (metacyclogenesis). No peaks of ubiquitin-mediated degradation were observed and the profile of ubiquitinated conjugates was similar at all stages of differentiation. However, an analysis of carbonylated proteins showed significant variation in oxidized protein levels at the various stages of differentiation and the proteasome inhibition also increased oxidized protein levels. Our data suggest that different proteasome complexes coexist during metacyclogenesis. The 20S proteasome may be free or linked to regulatory particles (PA700, PA26 and PA200), at specific cell sites and the coordinated action of these complexes would make it possible for proteolysis of ubiquitin-tagged proteins and oxidized proteins, to coexist in the cell.
authors.affiliation: Instituto Carlos Chagas/FIOCRUZ, Curitiba, Parana, Brazil.
authors.forename: Josiane
authors.initials: J
authors.lastname: Cardoso
authors.forename: Carla De Paula
authors.initials: Cde P
authors.lastname: Lima
authors.forename: Tiago
authors.initials: T
authors.lastname: Leal
authors.forename: Daniela F
authors.initials: DF
authors.lastname: Gradia
authors.forename: Stênio P
authors.initials: SP
authors.lastname: Fragoso
authors.forename: Samuel
authors.initials: S
authors.lastname: Goldenberg
authors.forename: Renata Guerra
authors.initials: RG
authors.lastname: De Sá
authors.forename: Marco A
authors.initials: MA
authors.lastname: Krieger
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006868:Hydrolysis; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D014349:Trypanosoma cruzi / Q000201:enzymology / Q000502:physiology*; D054875:Ubiquitination
chemical_list: D046988:Proteasome Endopeptidase Complex