Analysis of β-Amyloid Peptide -Binding Proteins in Microglial Cells

Abstract

Alzheimer's disease is the most common form of dementia in the elderly. Although � -amyloid peptide (A� ) has been considered major cause of Alzheimer pathology, molecular and cellular mechanisms of the disease development of Alzheimer have not been clarified yet. Presently Ahas been considered to induce neural cell death by direct penetration of aggregated form or indirect cell death by inflammatory responses induced by A� -activated microglia. In order to understand Ainduced microglial activation, we searched the proteins which bind to Ain activated microglial cell line. We stimulated Ra2 microglial cell line with A� . Activated Ra2 cells were immunoprecipitated with anti- Aand run the gel. Membrane was silver stained and bands were cut and digested with enzyme. They were analyzed by LC/MS/MS. We found that several proteins including myosin 9 and actin bound to A� . By the addition of A� , actin binding was enhanced and other proteins including IQGAP1, Plectin strongly bound to A� . These results indicate that Abinds to the proteins belonging to cellular cytoskeletal system.