Functional and structural comparison between protofibrils of rabbit muscle and human GAPDH

DEFONSI , E; VERA, C; CHAVES, S; TORRES-BUGEAU, C; MINAHK, C; BELLOMIO, A; AVILA, C; CHEHÍN, R

Villa Carlos Paz, Cordoba

Congreso; XLII Reunión Anual Sociedad Argentina de Biofisica; 2013

GAPDH is an ubiquitous enzyme that in addition to its central role in energy production presents highly diverse non-glycolitic functions in the intra or extracellular space. Several independent studies suggest that it might also be related to neurodegenerative diseases. We recently reported that highly sulfated GAGs like heparin and heparin sulphates, are able to trigger GAPDH amyloid aggregation. The GAPDH protofibrils formed during the early stages of the aggregation process are able to efficiently accelerate α-Sinucleína (AS) aggregation. We proposed that these protofibrils could play an important role sequestering the AS oligomeric species involved in amyloid disease spreading in the extracellular space. Still, all the experiments were performed using commercially available GAPDH from rabbit muscle. In this way the study of the ability of protofibrillar species from human GAPDH to neutralize AS toxic species acquire relevance. In the present work we have expressed and purified human GAPDH and compared the aggregation kinetics of human GAPDH vs. rabbit muscle GAPDH. Structural comparison of these proteins as well as their aggregation intermediates and fibrils were performed by spectroscopic techniques. The ability of the different protofibrils to neutralize the membrane perturbation capability of AS oligomers was also compared. The relevance of the different mutation of human and rabbit GAPDH in heparin binding and aggregation was assessed using bioinformatic tools. This study represents a milestone in the assessment of the feasibility of using heparin-induced-GAPDH protofibrilsas a therapeutic agent in the treatment of PD.