Biochemical and structural studies on human RILP-like protein 1. Its identification as human GOSPEL

INGARAMO MC; ROMERO JM; CURTINO JA; CARRIZO ME

Mendoza

Congreso; XLVIII Annual Meeting SAIB; 2012

SAIB. Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multi-functional protein, which is also involved in cell death, frequently associated with oxidative and nitrosative stress. Reversible S-nitrosylation of GAPDH facilitates its binding to the E3-ubiquitin-ligase Siah1, which possesses a nuclear localization signal that promotes the translocation of the complex to the nucleus resulting in a cytotoxic effect. In rats, it has recently been described an interactor of GAPDH which interferes with the binding between GAPDH and Siah1, preventing the apoptotic role of these proteins in the nucleus. According to this function, the authors have designated the protein GOSPEL (GAPDH´s Competitor Of Siah1 Protein Enhances Life). S-nitrosylation of GOSPEL enhances GAPDH?GOSPEL binding and the neuroprotective actions of the protein. In a database search for GOSPEL homologues in humans, we identified a protein named RLP1 (RILP-like protein 1), which is 93% identical to GOSPEL. To analyze if it shares GOSPEL properties, we have prepared the recombinant human protein and studied its capacity to be S-nitrosylated and to bind to S-nitrosylated GAPDH. We have also made structural studies of the protein, including the effect of oxidative stress on its oligomerization state. Our results would suggest that the GOSPEL-mediated neuroprotective mechanism is conserved between rodents and humans.