Clusterin (Apolipoprotein J) is a 75-80 kDa heterodimeric glycoprotein produced by a wide array of tissues and found in most biologic fluids (PMID: 7648419; 11906815). It is encoded by one single gene and cleaved posttranslationally into alpha (34-36 kDa) and beta (36-39 kDa) subunits prior to secretion from the cell. Many functions have been described for clusterin, including regulating apoptosis, transporting lipids, controlling cell interactions, regulating complement (PMID: 10694874).