CircuLex Human Clusterin/Apo-J ELISA Kit

Clusterin, also called apolipoprotein J, sulfated glycoprotein-2, and testosterone-repressed prostate message-2, is a highly conserved secreted heterodimeric glycoprotein constitutively expressed by diverse epithelial cells. Clusterin has been implicated in diverse physiological processes, including lipid transportation (1), complement inhibition (1), tissue remodeling (2), membrane recycling (3), clearance of cellular debris (4), regulation of apoptosis, membrane protection, and promotion of cell-cell interactions (5). Clusterin is induced in injured organs in various disease states, such as Alzheimer's disease, atherosclerosis, myocardial infarction, and multiple forms of acute and chronic renal disease (5, 6). Clusterin has been shown to associate with both normal in vitro aging, namely replicative senescence, as well as with stress induced premature senescence. In vivo, the protein is up-regulated in many severe physiological disturbances that relate to advanced aging, including accumulation in the artery wall during the development of atherosclerosis. In cancer, clusterin up-regulation has been described in renal cell carcinoma (7), breast carcinoma (8), ovarian cancer (9), anaplastic large cell lymphomas (10), desmoplastic melanoma (11), transitional cell carcinoma of the bladder (12), pancreatic cancer (13), and serous carcinoma and hepatocellular carcinoma (14). However, a number of tumor processes where clusterin is downregulated have also been described such as esophageal squamous cell carcinoma (15), testicular germ cell tumors (16) and prostate cancer (17). The structure of clusterin has not provided much insight into function. Mammalian clusterins are approximately 80-kDa heterodimers (18, 19) consisting of two 40-kDa chains joined by a unique five-disulfide-bond motif (20). The protein has limited homology to other proteins and lacks clear functional motifs (18). It does contain three putative amphipathic ?-helical regions, which could allow it to interact with lipids and hydrophobic regions of other proteins (21).