Interaction of TPPP/p25 protein with glyceraldehyde‐3‐phosphate dehydrogenase and their co‐localization in Lewy bodies

TPPP/p25, a flexible unstructured protein, binds to tubulin and induces aberrant microtubule assemblies. We identified hereby glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) as a new interacting partner of TPPP/p25. The immunoprecipitation and affinity chromatographic experiments with bovine brain cell‐free extract revealed that the interaction was salt and NAD + sensitive while ELISA showed resistant and firm association of the two isolated proteins. In transfected HeLa cells at low expression level of EGFP‐TPPP/p25, while the green fusion protein aligned at the microtubular network, GAPDH distributed uniformly in the cytosol. However, at high expression level, GAPDH co‐localized with TPPP/p25 in the aggresome‐like aggregate. Immunohistochemistry showed enrichment of TPPP/p25 and GAPDH within the α‐synuclein positive Lewy body.