Functional and biophysical studies for LaSir2RP1, sirtuin of Leishmania amazonensis

• Grant number: 11/51534-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: December 01, 2011
• End date: May 31, 2012
• Field of knowledge: Biological Sciences - Biochemistry - Chemistry of Macromolecules
• Principal Investigator: Carlos Henrique Inacio Ramos
• Grantee: Melissa Regina Fessel
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 05/00462-8 - Protein folding, stability and structure, AP.TEM

Abstract

Sirtuins are members of a family of proteins that present NAD+-dependent deacetilase activity and are involved in many biological functions. A member of this family, named Sir2 Related Protein 1 (Sir2RP1), has already been characterized in some Leishmania and along the FAPESP project 2008/58617-5, we identified and characterized the L. amazonensis Sir2RP1 ortholog (LaSir2RP1) (Fessel et al., 2011). We investigated the protein by biophysical tools and confirmed that recombinant LaSir2RP1 is an active NAD+-dependent deacetilase. We also showed that LaSir2RP1 is a glycoprotein expressed in both parasite developmental forms and is secreted by both evolutive stages Also, LaSir2RP1 was immunolocalized into parasite cytoplasmic granules related to endoplasmic reticulum In order to evaluate the role of LaSir2RP1 at macrophage infection by L.amazonensis, we performed preliminary tests which suggested that exogen LaSir2RP1 interacts in vitro with mammalian cells and that the addition of this protein during the infection enhances the number of intracelular parasites. Now we propose the study of this phenomena including to investigate whether LaSir2RP1 promotes the enhancement of the macrophage phagocytic activity. If confirmed, these data will contribute to clarify the role of Sir2RP1 during host cells infection by Leishmania sp. Additionally, preliminary biophysical studies with LaSir2RP1 and resveratrol - a molecule that acts in mammalian sirtuin-dependent pathways and has leishmanicide activity-, suggest that they interact. Then, we propose perform additional assays to clarify the mechanism of interaction between resveratrol and LaSir2RP1 and the evaluation of potential effects into LaSir2RP1 in parasites treated with resveratrol. These results are expected to contribute to the knowledgement of structure and function of LaSir2RP1 and, also, to generate information about the mechanisms of leishmanicide action of resveratrol, which is still unkown. (AU)