Unusual localization of poly(ADP-ribose) metabolism-related enzymes in trypanosomatids

MARIANA SCHLESINGER; MARÍA LAURA KEVORKIAN; SALOMÉ VILCHEZ LARREA; MIRTHA M. FLAWIÁ; SILVIA H. FERNÁNDEZ VILLAMIL

Rosario

Congreso; 50th Annual Reunion SAIB; 2014

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

Poly(ADP-ribose) polymerase (PARP) and poly(ADP-ribose) glycohydrolase (PARG) are responsible for poly(ADP-ribose) polymer (PAR) metabolism and have been previously reported in trypanosomatids by our group. We investigated the localization of both enzymes in T.cruzi and T.brucei and, interestingly, PARP was localized mostly in the cytoplasm, whereas after oxidative stress (OS), PARP translocated to the nucleus. However, PARG was always nuclear. These localizations are opposite to what has been described in other organisms. In accordance, PAR formation was detected in the nuclei of the cells after OS. To date, neither potential nuclear localization signals nor other putative sequences involved in the protein targeting to different subcellular compartments in these parasites have been ascertained. By using parasites overexpressing the full length PARP and different PARP domains tagged to eYFP or HA, we demonstrate that the N-terminal region is crucial for PARP nuclear localization, even in the absence of OS. This data also implies that nuclear PAR metabolism may be regulated by the nucleus-cytoplasm shuttling of the only PARP. This particular localization of PARP in kynetoplastids could be related to the maintenance of the integrity of kinetoplast DNA (kDNA), essential for these parasites and could be a strategy to alternatively deliver the protein to this organelle or to the nucleus.