[5] CLU is an extracellular molecular chaperone which binds to misfolded proteins in body fluids to neutralise their toxicity and mediate their cellular uptake by receptor-mediated endocytosis.

[13] Clusterin was first identified in ram rete testis fluid where it was shown to elicit in vitro clustering of rat Sertoli cells and erythrocytes, hence its name.

CLU has been suggested to promote cell survival by a number of means, including inhibition of BAX on the mitochondrial membrane, activation of the phosphatidylinositol 3-kinase/protein kinase B pathway, modulation of extracellular signal-regulated kinase (ERK) 1/2 signaling and matrix metallopeptidase-9 expression, promotion of angiogenesis, and mediation of the nuclear factor kappa B (NF-κB) pathway.

Meanwhile, its downregulation allows for p53 activation, which then skews the proapoptotic:antiapoptotic ratio of present Bcl-2 family members, resulting in mitochondrial dysfunction and cell death.

[8] CLU may promote tumorigenesis by facilitating BAX-KLU70 binding and, consequently, preventing BAX from localizing to the outer mitochondrial membrane to stimulate cell death.

As evident by its key roles in cancer development, CLU can serve as a therapeutic target for fighting tumor growth and chemoresistance.

[9] In addition to the above diseases, CLU has been linked to other conditions resulting from oxidative damage, including aging, glomerulonephritis, atherosclerosis, and myocardial infarction.