analysis of proteasomal proteolysis during the in vitro metacyclogenesis of trypanosoma cruzi分析蛋白酶体蛋白水解作用在体外metacyclogenesis鲁兹锥体.pdfVIP

Analysis of Proteasomal Proteolysis during the In Vitro Metacyclogenesis of Trypanosoma cruzi 1 1 2 1 ˆ 1 Josiane Cardoso , Carla De Paula Lima , Tiago Leal , Daniela F. Gradia , Stenio P. Fragoso , Samuel 1 ´ 2 1 Goldenberg , Renata Guerra De Sa , Marco A. Krieger * 1 Instituto Carlos Chagas/FIOCRUZ, Curitiba, Parana, Brazil, 2 Universidade Federal de Ouro Preto/UFOP, Ouro Preto, Minas Gerais, Brazil 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