Clusterin, Human, ELISA kit

Clusterin, also called apolipoprotein-J, is a 80KDa heterodimeric glycoprotein (in blood) implicated in regulation of several biological processes, like lipid transport, cell adhesion and complement regulation. It consists of two polypeptide chains linked by disulfide bonds. The protein is expressed in most tissues of the body. From its precursor different isoforms can be generated, each with its own function, as well intracellularly as extracellularly. Secreted clusterin is the most common isoform. Inhibition of complement by clusterin, together with vitronectin and CD59, protects host cells from complement destruction via membrane attack complex (MAC) mediated cell lysis. Clusterin prevents Zn2+ induced binding of C9 to C5b-8 & C5b-9 and prevents C5b-7 membrane attachment. Thereby preventing spread to nearby cells through the selfamplifying properties of the complement cascade. The lipid-like character of clusterin probably associates with the mechanism of prevention by clusterin of MAC incorporation into the cell membrane. Although the majority of proteins remains bound to the complex, this explains why a fraction of clusterin dissociates from sTCC in the presence of detergents. It has been describe that the amount of active heterodimeric clusterin is <10%. Therefore, the
degree of reduction of complement mediated cytolysis is dependent on the local conditions and opens a window of regulation in function and time and the role of other inhibitors herein.
Besides its role in inhibition of complement mediated cell damage, it is associated with multiple diseases like Alzheimer’s disease, atherosclerosis and autoimmune disorders. For example, clusterin levels are elevated in patients with early rheumatoid arthritis and decreased in some groups of psoriatic patients.