title: Expression and cellular trafficking of GP82 and GP90 glycoproteins during Trypanosoma cruzi metacyclogenesis.
abstract: BACKGROUND
  The transformation of noninfective epimastigotes into infective metacyclic trypomastigotes (metacyclogenesis) is a fundamental step in the life cycle of Trypanosoma cruzi, comprising several morphological and biochemical changes. GP82 and GP90 are glycoproteins expressed at the surface of metacyclic trypomastigote, with opposite roles in mammalian cell invasion. GP82 is an adhesin that promotes cell invasion, while GP90 acts as a negative regulator of parasite internalization. Our understanding of the synthesis and intracellular trafficking of GP82 and GP90 during metacyclogenesis is still limited. Therefore, we decided to determine whether GP82 and GP90 are expressed only in fully differentiated metacyclic forms or they start to be expressed in intermediate forms undergoing differentiation.
  
  
  METHODS
  Parasite populations enriched in intermediate forms undergoing differentiation were analyzed by quantitative real-time PCR, Western blot, flow cytometry and immunofluorescence to assess GP82 and GP90 expression.
  
  
  RESULTS
  We found that GP82 and GP90 mRNAs and proteins are expressed in intermediate forms and reach higher levels in fully differentiated metacyclic forms. Surprisingly, GP82 and GP90 presented distinct cellular localizations in intermediate forms compared to metacyclic trypomastigotes. In intermediate forms, GP82 is localized in organelles at the posterior region and colocalizes with cruzipain, while GP90 is localized at the flagellar pocket region.
  
  
  CONCLUSIONS
  This study discloses new aspects of protein expression and trafficking during T. cruzi differentiation by showing that the machinery involved in GP82 and GP90 gene expression starts to operate early in the differentiation process and that different secretion pathways are responsible for delivering these glycoproteins toward the cell surface.
authors: Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP 04023-062, Brazil.
authors: Ethel
authors: E
authors: Bayer-Santos
authors: Narcisa Leal
authors: NL
authors: Cunha-e-Silva
authors: Nobuko
authors: N
authors: Yoshida
authors: José
authors: J
authors: Franco da Silveira
mesh_terms: D000818:Animals; D015153:Blotting, Western; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D051379:Mice; D021381:Protein Transport; D015800:Protozoan Proteins / Q000096:biosynthesis*; D060888:Real-Time Polymerase Chain Reaction; D014349:Trypanosoma cruzi / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000096:biosynthesis*
chemical_list: D015800:Protozoan Proteins; D014643:Variant Surface Glycoproteins, Trypanosoma; C527132:glycoprotein GP82, Trypanosoma cruzi; C044186:glycoprotein GP90, Trypanosoma cruzi
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