GOSPEL enhances in vitro nitric oxide-induced aggregation of GAPDH

GONZALEZ, MARÍA C.; INGARAMO, MARÍA C.; ROMERO, JORGE M.; CURTINO, JUAN A.; CARRIZO, MARÍA E.

Carlos Paz, Córdoba

Congreso; XLII Reunión Anual de la Sociedad Argentina de Biofísica (SAB); 2013

Sociedad Argentina de Biofísica (SAB)

Among its many functions, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has a proapoptotic role associated with oxidative and nitrosative stress. Nitric oxide stress leads to reversible S-nitrosylation of the active site cysteine of GAPDH. When S-nitrosylated GAPDH binds to the E3-ubiquitin-ligase Siah1 which possesses a nuclear localization signal that promotes the translocation of the complex to the nucleus, where both proteins have cytotoxic effects. This cascade is regulated by S-nitrosylated GOSPEL (GAPDH´s competitor Of Siah Protein Enhances Life) whose association with GAPDH prevents the cytotoxic interaction GAPDH-Siah1 (1). Oxidative stress, produced either by hydrogen peroxide or nitric oxide, can also promote the formation of amyloid-like aggregates of GAPDH through disulfide bonds involving its active site cysteine (2). It is worth mentioning that GAPDH has also been found deposited as insoluble aggregates in some neurodegenerative diseases. Here we present the analysis of the effect of GOSPEL on the in vitro aggregation of GAPDH induced by nitric oxide. Our results indicate that, under these conditions, both proteins co-aggregate and that the aggregation of GAPDH was enhanced in the presence of GOSPEL. Our work also includes the characterization of the aggregates obtained and the study of the nature of the interaction between the proteins therein.  References 1. Sen, N. et al. (2009) Neuron 63, 81-91. 2. Nakajima, H. et al. (2007) J. Biol. Chem. 282, 26562?26574.