Clusterin is one of the central stress response proteins. It exists in two variants. The major longer secreted form of clusterin (sCLU) exerts an anti-apoptotic function and the nuclear form (nCLU) has a pro-apoptotic function.
sCLU binds extracellularly to stressed and unfolded proteins to form a clusterin – damaged protein complex. This complex is subjected to either interaction with other chaperones in order to refold the damaged protein or interaction with cellular receptors resulting in lysosomal or proteasomal degradation inside the cell.