title: Trypanosoma cruzi: cruzipain and membrane-bound cysteine proteinase isoform(s) interacts with human alpha(2)-macroglobulin and pregnancy zone protein.
abstract: Plasmatic levels of pregnancy zone protein (PZP) increase in children with acute Chagas disease. PZP, as well as alpha2-macroglobulin (alpha2-M), are able to interact with Trypanosoma cruzi proteinases. The interaction of alpha2-M and PZP with cruzipain, the major cysteine proteinase of T. cruzi, was investigated. Several molecular changes on both alpha-M inhibitors under reaction with cruzipain were found. PAGE analysis showed: (i) formation of complexes of intermediate mobility and tetramerization of native alpha2-M and PZP, respectively; (ii) limited proteolysis of bait region in alpha2-M and PZP, and (iii) covalent binding of cruzipain to PZP and alpha2-M. Conformational and structural changes experimented by alpha-Ms correlate with modifications of the enzyme electrophoretic mobility and activity. Cruzipain-alpha-M complexes were also detected by gelatin SDS-PAGE and immunoblotting using polyclonal anti-cruzipain antibodies. Concomitantly, alpha2-M and PZP impaired the activity of cruzipain towards Bz-Pro-Phe-Arg-pNA substrate. In addition, alpha-Ms were able to form covalent complexes with membrane isoforms of cysteine proteinases cross-reacting with cruzipain. The present study suggests that both human alpha-macroglobulin inhibitors could prevent or minimize harmful action of cruzipain on host's molecules and hypothetically regulate parasite functions controlled by cruzipain.
authors.affiliation: Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, (5000), Argentina. amramos@bioclin.fcq.unc.edu.ar
authors.forename: Adrián M
authors.initials: AM
authors.lastname: Ramos
authors.forename: Vilma G
authors.initials: VG
authors.lastname: Duschak
authors.forename: Nelia M
authors.initials: NM
authors.lastname: Gerez de Burgos
authors.forename: Mariana
authors.initials: M
authors.lastname: Barboza
authors.forename: María S
authors.initials: MS
authors.lastname: Remedi
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Vides
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Chiabrando
mesh_terms: D000210:Acute-Phase Reaction / Q000097:blood; D000818:Animals; D014355:Chagas Disease / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007223:Infant; D008297:Male; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000378:metabolism*; D015800:Protozoan Proteins; D014349:Trypanosoma cruzi / Q000201:enzymology*; D000511:alpha-Macroglobulins / Q000378:metabolism*
chemical_list: D011257:Pregnancy Proteins; D015800:Protozoan Proteins; D000511:alpha-Macroglobulins; D003546:Cysteine Endopeptidases; C063214:cruzipain