RESUMO
Host cell invasion by Trypanosoma cruzi metacyclic trypomastigote (MT) is mediated by MT-specific surface molecule gp82, which binds to a still unidentified receptor, inducing lysosome spreading and exocytosis required for the parasitophorous vacuole formation. We examined the involvement of the major lysosome membrane-associated LAMP proteins in MT invasion. First, human epithelial HeLa cells were incubated with MT in the presence of antibody to LAMP-1 or LAMP-2. Antibody to LAMP-2, but not to LAMP-1, significantly reduced MT invasion. Next, HeLa cells depleted in LAMP-1 or LAMP-2 were generated. Cells deficient in LAMP-2, but not in LAMP-1, were significantly more resistant to MT invasion than wild-type controls. The possibility that LAMP-2 might be the receptor for gp82 was examined by co-immunoprecipitation assays. Protein A/G magnetic beads cross-linked with antibody directed to LAMP-1 or LAMP-2 were incubated with HeLa cell and MT detergent extracts. Gp82 bound to LAMP-2 but not to LAMP-1. Binding of the recombinant gp82 protein to wild-type and LAMP-1-deficient cells, which was dose dependent and saturable, had a similar profile and was much higher as compared with LAMP-2-depleted cells. These data indicate that MT invasion is accomplished through recognition of gp82 by its receptor LAMP-2.