Clusterin, also known as Apolipoprotein J (ApoJ), is a ubiquitous multifunctional glycoprotein that can interact with a broad spectrum of molecules such as complement components, various receptors, and the Alzheimer’s b-amyloid peptide. Clusterin is synthesized as a 449 amino acid polypeptide that is post-translationally cleaved at an internal bond between Arg 227 and Ser 228. Two subunits, α and β, are associated through disulfide bonds. The α subunit corresponds to residues 23-227. The β subunit corresponds to residues 228-449. Clusterin expression is increased in Alzheimer’s disease brain tissue and clusterin-immunoreactive amyloid plaques are found associated with phospho-tau-positive dystrophic neurites and it has been suggested that clusterin facilitates the conversion of diffuse b-amyloid deposits into amyloid and enhances tau phosphorylation in neurites around these plaques.
