TcADKn an adenylate kinase of T. cruzi involved in ribosome biogenesis

MARÍA DE LOS MILAGROS CÁMARA, LEÓN A. BOUVIER, MARIANA R. MIRANDA Y CLAUDIO A. PEREIRA.

Mar del Plata

Congreso; IX Congreso Argentino de Protozoología y Enfermedades Parasitarias; 2011

sociedad argentina de protozoologia

Adenylate kinases (ADKs) are enzymes involved in cellular energetic homeostasis; they are involved in nucleotide interconversion. In typical eukaryotic cells, there are very few isoforms of ADKs however, in trypanosomatids there have been characterized a large number of isoforms. Nuclear ADKs have been recently characterized in several organisms; in yeast it has been proved that it is an essential protein involved in the ribosome?s small subunit processing. In this work we studied the nuclear ADK isoform (TcADKn) of T. cruzi. We measured the biochemical activity of this enzyme finding that it presents ADK and ATPase activity being the p-loop essential for both activities. We mapped the non-canonical nuclear localization signal, narrowing it to the amino terminal of the protein. Furthermore we studied the TcADKn localization and expression under different drugs or media treatments, and also along the parasites growth curve: transcription interruption and starvation delocalized TcADKn from the nucleus. Rapamycin treatments enhanced its nuclear localization, a typical effect observed for ribosomal proteins dependant on the mTOR pathway. We detected that the 3?UTR of TcADKn could be the responsible of the differential expression levels along the growth curve. Finally complementation assays in yeasts revealed that it could be involved in similar processes as its yeast homolog FAP7.