INVESTIGADORES
PARUSSINI GIMENEZ silvana fabiola
congresos y reuniones científicas
Título:
Cysteine proteinases in Trypanosoma cruzi and other Trypanosomatid parasites
Autor/es:
JUAN JOSÉ CAZZULO; CARLOS LABRIOLA; FABIOLA PARUSSINI; VILMA G. DUSCHAK; JAVIER MARTÍNEZ; BERTA FRANKE DE CAZZULO
Lugar:
Portoroz
Reunión:
Conferencia; 1st Meeting of the Slovenian Biochemical Society; 1995
Institución organizadora:
Slovenian Biochemical Society
Resumen:
Trypanosomatids are parasitic Protozoa, some of which cause diseases in man and cattle, and have considerable medical and economical importance. They contain, in general, high proteolytic activities, of which cysteine proteinases (CPs) are the most prominent. With few exceptions, the CPs from Trypanosomatids are encoded by a high number of gene copies, arrayed in head-to-tail tandems. These genes reveal the presence, in addition to a catalytic domain with high homology to enzymes in the papain family, of a C-terminal extension (C- T), which is some cases (cruzipain from Trypanosoma cruzi; congopain from T. congolense; the CPs from T. rangeli and  Crithidia jasciculata) is present in the mature enzyme, whereas in other cases (Leishmania mexicana, T. brucei) it is lost during processing. In the case of cruzipain, the C- T can be purified after self-proteolysis, and has been shown to be the place of a number of post-translational modifications, which probably contribute to most of the microhetero-geneities found in the natural mixture of isoforms. In addition, the C- T is responsible for the immuno­reactivity of cruzipain, which is an immunodominant antigen in chronic Chagas disease. In several Trypanosomatids the expression of CPs in the different stages of the often complex life cycles is developmentally regulated. In the case of T. cruzi there is ample evidence showing that irreversible CP inhibitors, which inhibit cruzipain within living parasites, are able to block the differentiation steps of the life cycle, with little effect on the proliferative forms.