Proteomic Identification of Protein Targets for 15-Deoxy-Δ12,14-Prostaglandin J2 in Neuronal Plasma Membrane

15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) is one of factors contributed to the neurotoxicity of amyloid beta (A beta), a causative protein of Alzheimer's disease. Type 2 receptor for prostaglandin D-2 (DP2) and peroxysome-proliferator activated receptor gamma (PPAR gamma) are identified as the membrane receptor and the nuclear receptor for 15d-PGJ(2), respectively. Previously, we reported that the cytotoxicity of 15d-PGJ(2) was independent of DP2 and PPAR gamma, and suggested that 15d-PGJ(2) induced apoptosis through the novel specific binding sites of 15d-PGJ(2) different from DP2 and PPAR gamma. To relate the cytotoxicity of 15d-PGJ(2) to amyloidoses, we performed binding assay [H-3]15d-PGJ(2) and specified targets for 15d-PGJ(2) associated with cytotoxicity. In the various cell lines, there was a close correlation between the susceptibilities to 15d-PGJ(2) and fibrillar A beta. Specific binding sites of [H-3]15d-PGJ(2) were detected in rat cortical neurons and human bronchial smooth muscle cells. When the binding assay was performed in subcellular fractions of neurons, the specific binding sites of [H-3]15d-PGJ(2) were detected in plasma membrane, nuclear and cytosol, but not in microsome. A proteomic approach was used to identify protein targets for 15d-PGJ(2) in the plasma membrane. By using biotinylated 15d-PGJ(2), eleven proteins were identified as biotin-positive spots and classified into three different functional proteins: glycolytic enzymes (Enolase2, pyruvate kinase M1 (PKM1) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH)), molecular chaperones (heat shock protein 8 and T-complex protein 1 subunit alpha), cytoskeletal proteins (Actin beta, F-actin-capping protein, Tubulin beta and Internexin alpha). GAPDH, PKM1 and Tubulin beta are A beta-interacting proteins. Thus, the present study suggested that 15d-PGJ(2) plays an important role in amyloidoses not only in the central nervous system but also in the peripheral tissues.