NO-induced GAPDH aggregation is increased by GOSPEL protein and inhibited by NAD

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

Mar del Plata, Buenos Aires

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2015

Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

GOSPEL is the protein reported to compete with Siah1 for binding to GAPDH under S-nitrosylation-induced stress conditions, thus preventing GAPDH-bound Siah1 nuclear translocation and subsequent apoptosis. It is not known whether GOSPEL is able to affect the formation of amyloid-like GAPDH aggregates, which also occurs under NO oxidative stress conditions promoting cell death. Here we report the in vitro enhancement by GOSPEL of the GAPDH aggregation produced by the NO donor NOR3. The unique cysteine residue of GOSPEL was partially required for co-aggregation, since the cysteine-free GOSPEL mutant C47S produced a minor aggregation increase. GOSPEL did not affect the lag time preceding GAPDH aggregation but did accelerate this process once it has begun. Such acceleration is proposed to occur through its binding to disulfide-bond dimers and low molecular weight disulfide-crosslinked GAPDH oligomers which act as seed for further protein disulfide-interlink and insoluble aggregate formation. Both GAPDH aggregation and co-aggregation with GOSPEL were inhibited by NAD, a heretofore not described protective effect of this coenzyme against the damaging consequences of oxidative stress. This is the first report on GOSPEL favoring the oxidized GAPDH aggregation involved in cell death, in opposite way to the helpful effect against the apoptotic nuclear translocation of the glycolytic enzyme.