CHO cells expressing the human P5-ATPase ATP13A2 are more sensitive to the toxic effects induced by the polyamine analog Paraquat

DE TEZANOS PINTO, FELICITAS Y ADAMO, HUGO P.; CORRADI, GERARDO R.; DE LA HERA, DIEGO P.; ADAMO HUGO P.

Puerto Madryn

Congreso; XLVI Congreso organizado por la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The P-type ion pumps are membrane transporters energized by hydrolysis of ATP. They have been classified into five subfamilies termed P1-P5. Five genes named ATP13A1-5 that belong to the group of P5-ATPases have been identified in humans. Mutations of the  ATP13A2 gene underlie a form of parkinson (PD). The ion transported by the P5-ATPases is not known; it was suggested that were Ca2+ transporters, nevertheless we have shown that this enzyme is not a Ca2+ transporting pump. It was recently reported that the deletion of the closely related P5-ATPase CATP-5 of C. elegans is responsible for the tolerant phenotype seen in the presence of the toxic polyamine analog norspermidine. We investigated the effect of ATP13A2 overexpression on the viability of CHO cells to the toxic polyamine analog paraquat (1,1´-dimethyl-4,4´-bipyridinium) by measuring the activity of the endogenous enzyme hexosaminidase. CHO cells expressing the ATP13A2 were eight times more sensible to paraquat treatment than CHO cells transfected with the empty vector. The quantization of paraquat-induced production of cellular reactive oxygen species (ROS) measured with the 5(6)-carboxy-2,7-dichlorodihydrofluorescein diacetate probe showed a significant  increase in CHO cells expressing the ATP13A2 pump. These results favor the idea that the P5-ATPase ATP13A2 is involved in polyamine transport.