title: Leishmania (Leishmania) amazonensis: differential expression of proteinases and cell-surface polypeptides in avirulent and virulent promastigotes.
abstract: A comparative study of proteolytic enzymes and cell-surface protein composition in virulent and avirulent Leishmania (Leishmania) amazonensis promastigote forms was carried out using one- and two-dimensional dodecyl sulfate sodium-polyacrylamide gel electrophoresis (SDS-PAGE). The surface iodinated protein profiles showed two major polypeptides of 65-60 and 50-47 kDa that were expressed in both virulent and avirulent promastigote forms. However, minor quantitative differences were observed in the cell-surface profile between the avirulent and virulent promastigotes. These included polypeptides of 115, 52, 45, 32, and 25 kDa that were preferentially expressed in the virulent forms. Two-dimensional SDS-PAGE showed an accentuated expression of acidic polypeptides; some of them differentially expressed in the promastigote forms analyzed. Live parasites treated with glycosylphosphatidylinositol (GPI)-specific phospholipase C (PLC) from Trypanosoma brucei and immunoprecipitated with the cross-reacting determinant (CRD) antibody recognized three major polypeptides of 65-60, 52, and 50-47 kDa, hence suggesting that these peptides were anchored to the plasma membrane domains through GPI anchor. Moreover, the polypeptides of 65-60 and 52 kDa were also recognized by the gp63 antiserum. Several metalloproteinase activities were similar in both virulent and avirulent promastigote forms, whereas cysteine proteinase activities, sensitive to E-64, were preferentially expressed in virulent promastigotes. These results suggest that cell-surface polypeptides and intracellular cysteine proteinases might play an important role in the virulence of L. (L.) amazonensis.
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Prof. Paulo de Góes, Centro de Ciências da Saúde, Bloco I, Universidade do Brasil (UFRJ), Ilha do Fundão, 21941-590 Rio de Janeiro, RJ, Brazil. rasoares@micro.ufrj.br
authors.forename: Rosangela Maria
authors.initials: RM
authors.lastname: de Araújo Soares
authors.forename: André Luis Souza
authors.initials: AL
authors.lastname: dos Santos
authors.forename: Myrna Cristina
authors.initials: MC
authors.lastname: Bonaldo
authors.forename: Arnaldo Feitosa Braga
authors.initials: AF
authors.lastname: de Andrade
authors.forename: Celuta Sales
authors.initials: CS
authors.lastname: Alviano
authors.forename: Jayme
authors.initials: J
authors.lastname: Angluster
authors.forename: Samuel
authors.initials: S
authors.lastname: Goldenberg
mesh_terms: D000818:Animals; D006224:Cricetinae; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000032:analysis / Q000096:biosynthesis*; D006801:Humans; D007894:Leishmania mexicana / Q000201:enzymology / Q000378:metabolism / Q000472:pathogenicity*; D008565:Membrane Proteins / Q000032:analysis / Q000096:biosynthesis*; D051379:Mice; D011233:Precipitin Tests; D015800:Protozoan Proteins / Q000032:analysis / Q000096:biosynthesis*; D014774:Virulence
chemical_list: D008565:Membrane Proteins; D015800:Protozoan Proteins; D010450:Endopeptidases