Structural Characterization of Heparin-induced GAPDH Protofibrils Preventing alpha-synuclein Oligomeric Species Toxicity

AVILA C.; TORRES-BUGEAU C.; BARBOSA L.; MORANDÉ SALES E.; OUIDJA O.; SOCIAS B.; CELEJ S.; RAISMAN VOZARI R.; PAPY GARCÍA D.; ITRI R.; CHEHÍN R.

JOURNAL OF BIOLOGICAL CHEMISTRY

AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Lugar: Bethesda, Maryland; Año: 2014 vol. 289 p. 13838 - 13850

0021-9258

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional enzyme that has been associated to neurodegenerative diseases. GAPDH colocalizes with alpha synuclein in amyloid aggregates in postmortem tissue of patients with sporadic Parkinson disease and promotes the formation of Lewy body-like inclusions in cell culture. In a previous work, we showed that glycosaminoglycans-induced GAPDH prefibrilar species accelerates the conversion of alpha synuclein to fibrils. However, it remained to be determined whether the interplay among glycosaminoglycans, GAPDH and alpha synuclein has a role in pathological states. Here we demonstrate that the toxic effect exerted by alpha synuclein oligomers in dopaminergic cell culture is abolished in the presence of GAPDH prefibrilar species Structural analysis of prefibrilar GAPDH performed by Small angle X-ray scattering, showed a particle compatible with a protofibril. This protofibril is shaped as a cylinder 22 nm long and cross-section diameter of 12 nm. Using biocomputational techniques we obtained the first allatom model of the GAPDH protofibril, which was validated by cross-linking coupled to mass spectrometry experiments. Since GAPDH can be secreted outside the cell where glycosaminoglycans are present, it seems plausible that GAPDH protofibrils could be assembled in the extracellular space kidnapping alpha synuclein toxic oligomers. Thus, the role of GAPDH protofibrils in neuronal proteostasis must be considered. The data reported herein could open alternative ways in development of therapeutic strategies against synucleinopathies like Parkinsons disease