Authors

Discussion

Trypanosoma cruzi possesses a complex life cycle that alternates between replicative and non-replicative forms. Replication protein A (RPA), the major eukaryotic single-stranded binding protein, is a heterotrimeric complex that participates in various vital functions in DNA metabolism. Immunoprecipitation, immunofluorescence and EdU incorporation assays suggested that TcRPA-1 and 2 form a complex and participates in RPA canonical functions. Moreover, TcRPA-2 heterozygous knockout cells (RPA2+/-) have a better efficiency in differentiation from epimastigote to metacyclic trypomastigote forms, suggesting that TcRPA can be somehow involved in differentiation process. Studying RPA in non-replicative forms, we found that RPA is exported from the nucleus. While in epimastigotes RPA was found at nuclear space, in metacyclic and bloodstream trypomastigotes, RPA was found in the cytoplasm. In amastigotes, RPA is presented in both compartments. A leucine rich nuclear export signal (NES) that is typically recognized by CRM-1 exportin was found in TcRPA-2. Preliminary results suggest a role for this protein in RPA nuclear export. SUMOylation, a post translational modification that is commonly involved in nuclear-cytoplasmic transport, can be involved in this regulation. We found a conserved SUMOylation site in TcRPA-1 and a first assay indeed detected sumoylation at RPA-1. The role of this modification in TcRPA shuttling is under investigation. &nbs